# 20 25 25 triangle

### Acute isosceles triangle.

Sides: a = 20   b = 25   c = 25

Area: T = 229.1298784748
Perimeter: p = 70
Semiperimeter: s = 35

Angle ∠ A = α = 47.15663569564° = 47°9'23″ = 0.82330336921 rad
Angle ∠ B = β = 66.42218215218° = 66°25'19″ = 1.15992794807 rad
Angle ∠ C = γ = 66.42218215218° = 66°25'19″ = 1.15992794807 rad

Height: ha = 22.91328784748
Height: hb = 18.33303027798
Height: hc = 18.33303027798

Median: ma = 22.91328784748
Median: mb = 18.87545860882
Median: mc = 18.87545860882

Inradius: r = 6.54765367071
Circumradius: R = 13.63986181397

Vertex coordinates: A[25; 0] B[0; 0] C[8; 18.33303027798]
Centroid: CG[11; 6.11101009266]
Coordinates of the circumscribed circle: U[12.5; 5.45554472559]
Coordinates of the inscribed circle: I[10; 6.54765367071]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 132.8443643044° = 132°50'37″ = 0.82330336921 rad
∠ B' = β' = 113.5788178478° = 113°34'41″ = 1.15992794807 rad
∠ C' = γ' = 113.5788178478° = 113°34'41″ = 1.15992794807 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.