# 11 13 15 triangle

### Acute scalene triangle.

Sides: a = 11   b = 13   c = 15

Area: T = 69.62989271783
Perimeter: p = 39
Semiperimeter: s = 19.5

Angle ∠ A = α = 45.57329959992° = 45°34'23″ = 0.79553988302 rad
Angle ∠ B = β = 57.56435627878° = 57°33'49″ = 1.00546736998 rad
Angle ∠ C = γ = 76.86334412131° = 76°51'48″ = 1.34215201236 rad

Height: ha = 12.66598049415
Height: hb = 10.71221426428
Height: hc = 9.28438569571

Median: ma = 12.91331715701
Median: mb = 11.4354596626
Median: mc = 9.42107218407

Inradius: r = 3.57107142143
Circumradius: R = 7.70215404622

Vertex coordinates: A[15; 0] B[0; 0] C[5.9; 9.28438569571]
Centroid: CG[6.96766666667; 3.09546189857]
Coordinates of the circumscribed circle: U[7.5; 1.7550350105]
Coordinates of the inscribed circle: I[6.5; 3.57107142143]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 134.4277004001° = 134°25'37″ = 0.79553988302 rad
∠ B' = β' = 122.4366437212° = 122°26'11″ = 1.00546736998 rad
∠ C' = γ' = 103.1376558787° = 103°8'12″ = 1.34215201236 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.