# 8 13 15 triangle

### Acute scalene triangle.

Sides: a = 8   b = 13   c = 15

Area: T = 51.96215242271
Perimeter: p = 36
Semiperimeter: s = 18

Angle ∠ A = α = 32.2044227504° = 32°12'15″ = 0.5622069803 rad
Angle ∠ B = β = 60° = 1.04771975512 rad
Angle ∠ C = γ = 87.7965772496° = 87°47'45″ = 1.53223252994 rad

Height: ha = 12.99903810568
Height: hb = 7.99440806503
Height: hc = 6.92882032303

Median: ma = 13.45436240471
Median: mb = 10.11218742081
Median: mc = 7.76220873481

Inradius: r = 2.88767513459
Circumradius: R = 7.50655534995

Vertex coordinates: A[15; 0] B[0; 0] C[4; 6.92882032303]
Centroid: CG[6.33333333333; 2.30994010768]
Coordinates of the circumscribed circle: U[7.5; 0.28986751346]
Coordinates of the inscribed circle: I[5; 2.88767513459]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 147.7965772496° = 147°47'45″ = 0.5622069803 rad
∠ B' = β' = 120° = 1.04771975512 rad
∠ C' = γ' = 92.2044227504° = 92°12'15″ = 1.53223252994 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.