# Isosceles triangle calculator

Please enter two properties of the isosceles triangle

Use symbols: a, b, h, T, p, A, B, C, r, R

You have entered side a and b.

### Acute isosceles triangle.

Sides: a = 142   b = 190   c = 142

Area: T = 10026.43987995
Perimeter: p = 474
Semiperimeter: s = 237

Angle ∠ A = α = 48.00989830931° = 48°32″ = 0.83879148255 rad
Angle ∠ B = β = 83.98220338138° = 83°58'55″ = 1.46657630026 rad
Angle ∠ C = γ = 48.00989830931° = 48°32″ = 0.83879148255 rad

Height: ha = 141.217744788
Height: hb = 105.5411461047
Height: hc = 141.217744788

Median: ma = 151.9577230825
Median: mb = 105.5411461047
Median: mc = 151.9577230825

Vertex coordinates: A[142; 0] B[0; 0] C[14.88773239437; 141.217744788]
Centroid: CG[52.29657746479; 47.07224826267]
Coordinates of the circumscribed circle: U[71; 63.90985335097]
Coordinates of the inscribed circle: I[47; 42.3065648943]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 131.9911016907° = 131°59'28″ = 0.83879148255 rad
∠ B' = β' = 96.01879661862° = 96°1'5″ = 1.46657630026 rad
∠ C' = γ' = 131.9911016907° = 131°59'28″ = 0.83879148255 rad

# How did we calculate this triangle?

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. ### 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    