Triangle calculator SSA
Triangle has two solutions with side c=142.50442398159 and with side c=30.70108409409
#1 Obtuse scalene triangle.
Sides: a = 100 b = 75 c = 142.50442398159Area: T = 3562.60659953985
Perimeter: p = 317.50442398159
Semiperimeter: s = 158.7522119908
Angle ∠ A = α = 41.81103148958° = 41°48'37″ = 0.73297276562 rad
Angle ∠ B = β = 30° = 0.52435987756 rad
Angle ∠ C = γ = 108.19896851042° = 108°11'23″ = 1.88882662218 rad
Height: ha = 71.2522119908
Height: hb = 95.0032826544
Height: hc = 50
Median: ma = 102.30545902331
Median: mb = 117.25496447021
Median: mc = 52.30333020814
Inradius: r = 22.44113128937
Circumradius: R = 75
Vertex coordinates: A[142.50442398159; 0] B[0; 0] C[86.60325403784; 50]
Centroid: CG[76.36989267315; 16.66766666667]
Coordinates of the circumscribed circle: U[71.2522119908; -23.41222918276]
Coordinates of the inscribed circle: I[83.7522119908; 22.44113128937]
Exterior (or external, outer) angles of the triangle:
∠ A' = α' = 138.19896851042° = 138°11'23″ = 0.73297276562 rad
∠ B' = β' = 150° = 0.52435987756 rad
∠ C' = γ' = 71.81103148958° = 71°48'37″ = 1.88882662218 rad
How did we calculate this triangle?
The calculation of the triangle has two phases. The first phase calculates all three sides of the triangle from the input parameters. The first phase is different for the different triangles query entered. The second phase calculates other triangle characteristics, such as angles, area, perimeter, heights, the center of gravity, circle radii, etc. Some input data also results in two to three correct triangle solutions (e.g., if the specified triangle area and two sides - typically resulting in both acute and obtuse) triangle).1. Use the Law of Cosines
We know the lengths of all three sides of the triangle, so the triangle is uniquely specified. Next, we calculate another of its characteristics - the same procedure for calculating the triangle from the known three sides SSS.
a=100 b=75 c=142.5
2. The triangle perimeter is the sum of the lengths of its three sides
p=a+b+c=100+75+142.5=317.5
3. Semiperimeter of the triangle
The semiperimeter of the triangle is half its perimeter. The semiperimeter frequently appears in formulas for triangles to be given a separate name. By the triangle inequality, the longest side length of a triangle is less than the semiperimeter.s=2p=2317.5=158.75
4. The triangle area using Heron's formula
Heron's formula gives the area of a triangle when the length of all three sides is known. There is no need to calculate angles or other distances in the triangle first. Heron's formula works equally well in all cases and types of triangles.T=s(s−a)(s−b)(s−c) T=158.75(158.75−100)(158.75−75)(158.75−142.5) T=12692161.48=3562.61
5. Calculate the heights of the triangle from its area.
There are many ways to find the height of the triangle. The easiest way is from the area and base length. The triangle area is half of the product of the base's length and height. Every side of the triangle can be a base; there are three bases and three heights (altitudes). Triangle height is the perpendicular line segment from a vertex to a line containing the base.T=2aha ha=a2 T=1002⋅ 3562.61=71.25 hb=b2 T=752⋅ 3562.61=95 hc=c2 T=142.52⋅ 3562.61=50
6. Calculation of the inner angles of the triangle using a Law of Cosines
The Law of Cosines is useful for finding a triangle's angles when we know all three sides. The cosine rule, also known as the Law of Cosines, relates all three sides of a triangle with an angle of a triangle. The Law of Cosines extrapolates the Pythagorean theorem for any triangle. Pythagorean theorem works only in a right triangle. Pythagorean theorem is a special case of the Law of Cosines and can be derived from it because the cosine of 90° is 0. It is best to find the angle opposite the longest side first. With the Law of Cosines, there is also no problem with obtuse angles as with the Law of Sines because the cosine function is negative for obtuse angles, zero for right, and positive for acute angles. We also use an inverse cosine called arccosine to determine the angle from the cosine value.a2=b2+c2−2bccosα α=arccos(2bcb2+c2−a2)=arccos(2⋅ 75⋅ 142.5752+142.52−1002)=41°48′37" b2=a2+c2−2accosβ β=arccos(2aca2+c2−b2)=arccos(2⋅ 100⋅ 142.51002+142.52−752)=30° γ=180°−α−β=180°−41°48′37"−30°=108°11′23"
7. Inradius
An incircle of a triangle is a tangent circle to each side. An incircle center is called an incenter and has a radius named inradius. All triangles have an incenter, and it always lies inside the triangle. The incenter is the intersection of the three-angle bisectors. The product of a triangle's inradius and semiperimeter (half the perimeter) is its area.T=rs r=sT=158.753562.61=22.44
8. Circumradius
The circumcircle of a triangle is a circle that passes through all of the triangle's vertices, and the circumradius of a triangle is the radius of the triangle's circumcircle. The circumcenter (center of the circumcircle) is the point where the perpendicular bisectors of a triangle intersect.R=4 rsabc=4⋅ 22.441⋅ 158.752100⋅ 75⋅ 142.5=75
9. Calculation of medians
A median of a triangle is a line segment joining a vertex to the opposite side's midpoint. Every triangle has three medians, and they all intersect each other at the triangle's centroid. The centroid divides each median into parts in the ratio of 2:1, with the centroid being twice as close to the midpoint of a side as it is to the opposite vertex. We use Apollonius's theorem to calculate a median's length from its side's lengths.ma=22b2+2c2−a2=22⋅ 752+2⋅ 142.52−1002=102.305 mb=22c2+2a2−b2=22⋅ 142.52+2⋅ 1002−752=117.25 mc=22a2+2b2−c2=22⋅ 1002+2⋅ 752−142.52=52.303
#2 Obtuse scalene triangle.
Sides: a = 100 b = 75 c = 30.70108409409Area: T = 767.52110235237
Perimeter: p = 205.70108409409
Semiperimeter: s = 102.85504204705
Angle ∠ A = α = 138.19896851042° = 138°11'23″ = 2.41218649974 rad
Angle ∠ B = β = 30° = 0.52435987756 rad
Angle ∠ C = γ = 11.81103148958° = 11°48'37″ = 0.20661288806 rad
Height: ha = 15.35504204705
Height: hb = 20.4677227294
Height: hc = 50
Median: ma = 27.99659071516
Median: mb = 63.75875157706
Median: mc = 87.04551870661
Inradius: r = 7.46224976739
Circumradius: R = 75
Vertex coordinates: A[30.70108409409; 0] B[0; 0] C[86.60325403784; 50]
Centroid: CG[39.10111271065; 16.66766666667]
Coordinates of the circumscribed circle: U[15.35504204705; 73.41222918276]
Coordinates of the inscribed circle: I[27.85504204705; 7.46224976739]
Exterior (or external, outer) angles of the triangle:
∠ A' = α' = 41.81103148958° = 41°48'37″ = 2.41218649974 rad
∠ B' = β' = 150° = 0.52435987756 rad
∠ C' = γ' = 168.19896851042° = 168°11'23″ = 0.20661288806 rad
Calculate another triangle
How did we calculate this triangle?
The calculation of the triangle has two phases. The first phase calculates all three sides of the triangle from the input parameters. The first phase is different for the different triangles query entered. The second phase calculates other triangle characteristics, such as angles, area, perimeter, heights, the center of gravity, circle radii, etc. Some input data also results in two to three correct triangle solutions (e.g., if the specified triangle area and two sides - typically resulting in both acute and obtuse) triangle).1. Use the Law of Cosines
We know the lengths of all three sides of the triangle, so the triangle is uniquely specified. Next, we calculate another of its characteristics - the same procedure for calculating the triangle from the known three sides SSS.
a=100 b=75 c=30.7
2. The triangle perimeter is the sum of the lengths of its three sides
p=a+b+c=100+75+30.7=205.7
3. Semiperimeter of the triangle
The semiperimeter of the triangle is half its perimeter. The semiperimeter frequently appears in formulas for triangles to be given a separate name. By the triangle inequality, the longest side length of a triangle is less than the semiperimeter.s=2p=2205.7=102.85
4. The triangle area using Heron's formula
Heron's formula gives the area of a triangle when the length of all three sides is known. There is no need to calculate angles or other distances in the triangle first. Heron's formula works equally well in all cases and types of triangles.T=s(s−a)(s−b)(s−c) T=102.85(102.85−100)(102.85−75)(102.85−30.7) T=589088.52=767.52
5. Calculate the heights of the triangle from its area.
There are many ways to find the height of the triangle. The easiest way is from the area and base length. The triangle area is half of the product of the base's length and height. Every side of the triangle can be a base; there are three bases and three heights (altitudes). Triangle height is the perpendicular line segment from a vertex to a line containing the base.T=2aha ha=a2 T=1002⋅ 767.52=15.35 hb=b2 T=752⋅ 767.52=20.47 hc=c2 T=30.72⋅ 767.52=50
6. Calculation of the inner angles of the triangle using a Law of Cosines
The Law of Cosines is useful for finding a triangle's angles when we know all three sides. The cosine rule, also known as the Law of Cosines, relates all three sides of a triangle with an angle of a triangle. The Law of Cosines extrapolates the Pythagorean theorem for any triangle. Pythagorean theorem works only in a right triangle. Pythagorean theorem is a special case of the Law of Cosines and can be derived from it because the cosine of 90° is 0. It is best to find the angle opposite the longest side first. With the Law of Cosines, there is also no problem with obtuse angles as with the Law of Sines because the cosine function is negative for obtuse angles, zero for right, and positive for acute angles. We also use an inverse cosine called arccosine to determine the angle from the cosine value.a2=b2+c2−2bccosα α=arccos(2bcb2+c2−a2)=arccos(2⋅ 75⋅ 30.7752+30.72−1002)=138°11′23" b2=a2+c2−2accosβ β=arccos(2aca2+c2−b2)=arccos(2⋅ 100⋅ 30.71002+30.72−752)=30° γ=180°−α−β=180°−138°11′23"−30°=11°48′37"
7. Inradius
An incircle of a triangle is a tangent circle to each side. An incircle center is called an incenter and has a radius named inradius. All triangles have an incenter, and it always lies inside the triangle. The incenter is the intersection of the three-angle bisectors. The product of a triangle's inradius and semiperimeter (half the perimeter) is its area.T=rs r=sT=102.85767.52=7.46
8. Circumradius
The circumcircle of a triangle is a circle that passes through all of the triangle's vertices, and the circumradius of a triangle is the radius of the triangle's circumcircle. The circumcenter (center of the circumcircle) is the point where the perpendicular bisectors of a triangle intersect.R=4 rsabc=4⋅ 7.462⋅ 102.85100⋅ 75⋅ 30.7=75
9. Calculation of medians
A median of a triangle is a line segment joining a vertex to the opposite side's midpoint. Every triangle has three medians, and they all intersect each other at the triangle's centroid. The centroid divides each median into parts in the ratio of 2:1, with the centroid being twice as close to the midpoint of a side as it is to the opposite vertex. We use Apollonius's theorem to calculate a median's length from its side's lengths.ma=22b2+2c2−a2=22⋅ 752+2⋅ 30.72−1002=27.996 mb=22c2+2a2−b2=22⋅ 30.72+2⋅ 1002−752=63.758 mc=22a2+2b2−c2=22⋅ 1002+2⋅ 752−30.72=87.045
Calculate another triangle
Look also at our friend's collection of math problems and questions:
- triangle
- right triangle
- Heron's formula
- The Law of Sines
- The Law of Cosines
- Pythagorean theorem
- triangle inequality
- similarity of triangles
- The right triangle altitude theorem
