# 40 50 80 triangle

### Obtuse scalene triangle.

Sides: a = 40   b = 50   c = 80

Area: T = 818.1533408598
Perimeter: p = 170
Semiperimeter: s = 85

Angle ∠ A = α = 24.14768479965° = 24°8'49″ = 0.42114420015 rad
Angle ∠ B = β = 30.75435198081° = 30°45'13″ = 0.53767501772 rad
Angle ∠ C = γ = 125.1099632195° = 125°5'59″ = 2.18334004748 rad

Height: ha = 40.90876704299
Height: hb = 32.72661363439
Height: hc = 20.45438352149

Median: ma = 63.64396103068
Median: mb = 58.09547501931
Median: mc = 21.21332034356

Vertex coordinates: A[80; 0] B[0; 0] C[34.375; 20.45438352149]
Centroid: CG[38.125; 6.81879450716]
Coordinates of the circumscribed circle: U[40; -28.11220872422]
Coordinates of the inscribed circle: I[35; 9.62553342188]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 155.8533152003° = 155°51'11″ = 0.42114420015 rad
∠ B' = β' = 149.2466480192° = 149°14'47″ = 0.53767501772 rad
∠ C' = γ' = 54.99003678046° = 54°54'1″ = 2.18334004748 rad

# How did we calculate this triangle? ### 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    