# 130 90 66.2 triangle

### Obtuse scalene triangle.

Sides: a = 130   b = 90   c = 66.2

Area: T = 2766.724436789
Perimeter: p = 286.2
Semiperimeter: s = 143.1

Angle ∠ A = α = 111.7660341514° = 111°45'37″ = 1.95105859326 rad
Angle ∠ B = β = 40.01440683351° = 40°51″ = 0.69883772396 rad
Angle ∠ C = γ = 28.2265590151° = 28°13'32″ = 0.49326294815 rad

Height: ha = 42.56549902753
Height: hb = 61.4832763731
Height: hc = 83.58768389092

Median: ma = 44.90223384692
Median: mb = 92.82435961381
Median: mc = 106.79113386

Inradius: r = 19.33442024311
Circumradius: R = 69.98770945754

Vertex coordinates: A[66.2; 0] B[0; 0] C[99.56552567976; 83.58768389092]
Centroid: CG[55.25550855992; 27.86222796364]
Coordinates of the circumscribed circle: U[33.1; 61.66550906682]
Coordinates of the inscribed circle: I[53.1; 19.33442024311]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 68.24396584861° = 68°14'23″ = 1.95105859326 rad
∠ B' = β' = 139.9865931665° = 139°59'9″ = 0.69883772396 rad
∠ C' = γ' = 151.7744409849° = 151°46'28″ = 0.49326294815 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    