# Isosceles triangle calculator (p)

Please enter two properties of the isosceles triangle

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

You have entered perimeter p and angle γ.

### Right isosceles triangle.

Sides: a = 13.18801948466   b = 13.18801948466   c = 18.64396103068

Area: T = 86.85987680972
Perimeter: p = 45
Semiperimeter: s = 22.5

Angle ∠ A = α = 45° = 0.78553981634 rad
Angle ∠ B = β = 45° = 0.78553981634 rad
Angle ∠ C = γ = 90° = 1.57107963268 rad

Height: ha = 13.18801948466
Height: hb = 13.18801948466
Height: hc = 9.32198051534

Median: ma = 14.73659058169
Median: mb = 14.73659058169
Median: mc = 9.32198051534

Vertex coordinates: A[18.64396103068; 0] B[0; 0] C[9.32198051534; 9.32198051534]
Centroid: CG[9.32198051534; 3.10766017178]
Coordinates of the circumscribed circle: U[9.32198051534; 0]
Coordinates of the inscribed circle: I[9.32198051534; 3.86603896932]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 135° = 0.78553981634 rad
∠ B' = β' = 135° = 0.78553981634 rad
∠ C' = γ' = 90° = 1.57107963268 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    