# Isosceles triangle calculator (a)

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 perimeter p.

### Acute isosceles triangle.

Sides: a = 76   b = 76   c = 99

Area: T = 2854.631113861
Perimeter: p = 251
Semiperimeter: s = 125.5

Angle ∠ A = α = 49.35991196256° = 49°21'33″ = 0.86114791534 rad
Angle ∠ B = β = 49.35991196256° = 49°21'33″ = 0.86114791534 rad
Angle ∠ C = γ = 81.28217607489° = 81°16'54″ = 1.41986343469 rad

Height: ha = 75.12218720686
Height: hb = 75.12218720686
Height: hc = 57.66993159314

Median: ma = 79.65223697074
Median: mb = 79.65223697074
Median: mc = 57.66993159314

Inradius: r = 22.74660648495
Circumradius: R = 50.0798624193

Vertex coordinates: A[99; 0] B[0; 0] C[49.5; 57.66993159314]
Centroid: CG[49.5; 19.22331053105]
Coordinates of the circumscribed circle: U[49.5; 7.59106917384]
Coordinates of the inscribed circle: I[49.5; 22.74660648495]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 130.6410880374° = 130°38'27″ = 0.86114791534 rad
∠ B' = β' = 130.6410880374° = 130°38'27″ = 0.86114791534 rad
∠ C' = γ' = 98.71882392511° = 98°43'6″ = 1.41986343469 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 ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.