# Triangle calculator

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

### Right scalene triangle.

Sides: a = 288.0076944361   b = 258   c = 128

Area: T = 16512
Perimeter: p = 674.0076944361
Semiperimeter: s = 337.003347218

Angle ∠ A = α = 90° = 1.57107963268 rad
Angle ∠ B = β = 63.61328854543° = 63°36'46″ = 1.11102542979 rad
Angle ∠ C = γ = 26.38771145457° = 26°23'14″ = 0.46105420289 rad

Height: ha = 114.6643901849
Height: hb = 128
Height: hc = 258

Median: ma = 144.003347218
Median: mb = 181.7287818454
Median: mc = 265.8199487623

Inradius: r = 48.99765278196
Circumradius: R = 144.003347218

Vertex coordinates: A[128; 0] B[0; 0] C[128; 258]
Centroid: CG[85.33333333333; 86]
Coordinates of the circumscribed circle: U[64; 129]
Coordinates of the inscribed circle: I[79.00334721804; 48.99765278196]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 90° = 1.57107963268 rad
∠ B' = β' = 116.3877114546° = 116°23'14″ = 1.11102542979 rad
∠ C' = γ' = 153.6132885454° = 153°36'46″ = 0.46105420289 rad

# How did we calculate this triangle?

### 1. Input data entered: side b, c and angle α. ### 2. Calculation of the third side a of the triangle using a Law of Cosines 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. ### 3. The triangle circumference is the sum of the lengths of its three sides ### 4. Semiperimeter of the triangle ### 5. The triangle area using Heron's formula ### 6. Calculate the heights of the triangle from its area. ### 7. Calculation of the inner angles of the triangle using a Law of Cosines    