# 13 30 30 triangle

### Acute isosceles triangle.

Sides: a = 13   b = 30   c = 30

Area: T = 190.3687900393
Perimeter: p = 73
Semiperimeter: s = 36.5

Angle ∠ A = α = 25.02766507258° = 25°1'36″ = 0.43767974559 rad
Angle ∠ B = β = 77.48766746371° = 77°29'12″ = 1.35223975988 rad
Angle ∠ C = γ = 77.48766746371° = 77°29'12″ = 1.35223975988 rad

Height: ha = 29.28773692912
Height: hb = 12.69111933595
Height: hc = 12.69111933595

Median: ma = 29.28773692912
Median: mb = 17.59326120858
Median: mc = 17.59326120858

Inradius: r = 5.21655589149
Circumradius: R = 15.36549853466

Vertex coordinates: A[30; 0] B[0; 0] C[2.81766666667; 12.69111933595]
Centroid: CG[10.93988888889; 4.23303977865]
Coordinates of the circumscribed circle: U[15; 3.32990801584]
Coordinates of the inscribed circle: I[6.5; 5.21655589149]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.9733349274° = 154°58'24″ = 0.43767974559 rad
∠ B' = β' = 102.5133325363° = 102°30'48″ = 1.35223975988 rad
∠ C' = γ' = 102.5133325363° = 102°30'48″ = 1.35223975988 rad

# How did we calculate this triangle?

Now we know the lengths of all three sides of the triangle and the triangle is uniquely determined. Next we calculate another its characteristics - same procedure as calculation of the triangle from the known three sides SSS. ### 1. The triangle circumference is the sum of the lengths of its three sides ### 2. Semiperimeter of the triangle ### 3. The triangle area using Heron's formula ### 4. Calculate the heights of the triangle from its area. ### 5. Calculation of the inner angles of the triangle using a Law of Cosines ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.