# 8 15 15 triangle

### Acute isosceles triangle.

Sides: a = 8   b = 15   c = 15

Area: T = 57.82773291792
Perimeter: p = 38
Semiperimeter: s = 19

Angle ∠ A = α = 30.93220199068° = 30°55'55″ = 0.54398655917 rad
Angle ∠ B = β = 74.53439900466° = 74°32'2″ = 1.3010863531 rad
Angle ∠ C = γ = 74.53439900466° = 74°32'2″ = 1.3010863531 rad

Height: ha = 14.45768322948
Height: hb = 7.71103105572
Height: hc = 7.71103105572

Median: ma = 14.45768322948
Median: mb = 9.3944147114
Median: mc = 9.3944147114

Inradius: r = 3.0443543641
Circumradius: R = 7.78217877185

Vertex coordinates: A[15; 0] B[0; 0] C[2.13333333333; 7.71103105572]
Centroid: CG[5.71111111111; 2.57701035191]
Coordinates of the circumscribed circle: U[7.5; 2.07551433916]
Coordinates of the inscribed circle: I[4; 3.0443543641]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 149.0687980093° = 149°4'5″ = 0.54398655917 rad
∠ B' = β' = 105.4666009953° = 105°27'58″ = 1.3010863531 rad
∠ C' = γ' = 105.4666009953° = 105°27'58″ = 1.3010863531 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.