# Triangle calculator

Please enter what you know about the triangle:
You have entered side a, b and c.

### Obtuse isosceles triangle.

Sides: a = 50   b = 50   c = 80

Area: T = 1200
Perimeter: p = 180
Semiperimeter: s = 90

Angle ∠ A = α = 36.87698976458° = 36°52'12″ = 0.64435011088 rad
Angle ∠ B = β = 36.87698976458° = 36°52'12″ = 0.64435011088 rad
Angle ∠ C = γ = 106.2660204708° = 106°15'37″ = 1.8554590436 rad

Height: ha = 48
Height: hb = 48
Height: hc = 30

Median: ma = 61.84765843843
Median: mb = 61.84765843843
Median: mc = 30

Inradius: r = 13.33333333333
Circumradius: R = 41.66766666667

Vertex coordinates: A[80; 0] B[0; 0] C[40; 30]
Centroid: CG[40; 10]
Coordinates of the circumscribed circle: U[40; -11.66766666667]
Coordinates of the inscribed circle: I[40; 13.33333333333]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.1330102354° = 143°7'48″ = 0.64435011088 rad
∠ B' = β' = 143.1330102354° = 143°7'48″ = 0.64435011088 rad
∠ C' = γ' = 73.74397952917° = 73°44'23″ = 1.8554590436 rad

# How did we calculate this triangle?

### 1. Input data entered: side a, b and c. ### 2. The triangle circumference is the sum of the lengths of its three sides ### 3. Semiperimeter of the triangle ### 4. The triangle area using Heron's formula ### 5. Calculate the heights of the triangle from its area. ### 6. Calculation of the inner angles of the triangle using a Law of Cosines    