Triangle calculator VC

Please enter the coordinates of the three vertices

Obtuse isosceles triangle.

Sides: a = 2.23660679775   b = 2.23660679775   c = 4.24326406871

Area: T = 1.5
Perimeter: p = 8.71547766421
Semiperimeter: s = 4.35773883211

Angle ∠ A = α = 18.43549488229° = 18°26'6″ = 0.32217505544 rad
Angle ∠ B = β = 18.43549488229° = 18°26'6″ = 0.32217505544 rad
Angle ∠ C = γ = 143.1330102354° = 143°7'48″ = 2.49880915448 rad

Height: ha = 1.34216407865
Height: hb = 1.34216407865
Height: hc = 0.70771067812

Median: ma = 3.20215621187
Median: mb = 3.20215621187
Median: mc = 0.70771067812

Inradius: r = 0.34442429018
Circumradius: R = 3.53655339059

Vertex coordinates: A[-1; 4] B[2; 7] C[1; 5]
Centroid: CG[0.66766666667; 5.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[1.03327287055; 0.34442429018]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 161.5655051177° = 161°33'54″ = 0.32217505544 rad
∠ B' = β' = 161.5655051177° = 161°33'54″ = 0.32217505544 rad
∠ C' = γ' = 36.87698976458° = 36°52'12″ = 2.49880915448 rad

How did we calculate this triangle?

1. We compute side a from coordinates using the Pythagorean theorem 2. We compute side b from coordinates using the Pythagorean theorem 3. We compute side c from coordinates using the Pythagorean theorem 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. 4. The triangle circumference is the sum of the lengths of its three sides 5. Semiperimeter of the triangle 6. The triangle area using Heron's formula 7. Calculate the heights of the triangle from its area. 8. Calculation of the inner angles of the triangle using a Law of Cosines     