# 11 15 15 triangle

### Acute isosceles triangle.

Sides: a = 11   b = 15   c = 15

Area: T = 76.75440715532
Perimeter: p = 41
Semiperimeter: s = 20.5

Angle ∠ A = α = 43.02203765338° = 43°1'13″ = 0.7510847216 rad
Angle ∠ B = β = 68.49898117331° = 68°29'23″ = 1.19553727188 rad
Angle ∠ C = γ = 68.49898117331° = 68°29'23″ = 1.19553727188 rad

Height: ha = 13.9555285737
Height: hb = 10.23438762071
Height: hc = 10.23438762071

Median: ma = 13.9555285737
Median: mb = 10.80550913925
Median: mc = 10.80550913925

Inradius: r = 3.74441010514
Circumradius: R = 8.06114615939

Vertex coordinates: A[15; 0] B[0; 0] C[4.03333333333; 10.23438762071]
Centroid: CG[6.34444444444; 3.4111292069]
Coordinates of the circumscribed circle: U[7.5; 2.95658692511]
Coordinates of the inscribed circle: I[5.5; 3.74441010514]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 136.9879623466° = 136°58'47″ = 0.7510847216 rad
∠ B' = β' = 111.5110188267° = 111°30'37″ = 1.19553727188 rad
∠ C' = γ' = 111.5110188267° = 111°30'37″ = 1.19553727188 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.