# 20 20 28 triangle

### Acute isosceles triangle.

Sides: a = 20   b = 20   c = 28

Area: T = 199.9659995999
Perimeter: p = 68
Semiperimeter: s = 34

Angle ∠ A = α = 45.57329959992° = 45°34'23″ = 0.79553988302 rad
Angle ∠ B = β = 45.57329959992° = 45°34'23″ = 0.79553988302 rad
Angle ∠ C = γ = 88.85440080016° = 88°51'14″ = 1.55107949932 rad

Height: ha = 19.99659995999
Height: hb = 19.99659995999
Height: hc = 14.28328568571

Median: ma = 22.18110730128
Median: mb = 22.18110730128
Median: mc = 14.28328568571

Inradius: r = 5.88111763529
Circumradius: R = 14.00328008403

Vertex coordinates: A[28; 0] B[0; 0] C[14; 14.28328568571]
Centroid: CG[14; 4.76109522857]
Coordinates of the circumscribed circle: U[14; 0.28800560168]
Coordinates of the inscribed circle: I[14; 5.88111763529]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 134.4277004001° = 134°25'37″ = 0.79553988302 rad
∠ B' = β' = 134.4277004001° = 134°25'37″ = 0.79553988302 rad
∠ C' = γ' = 91.14659919984° = 91°8'46″ = 1.55107949932 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.