# 15 17 28 triangle

### Obtuse scalene triangle.

Sides: a = 15   b = 17   c = 28

Area: T = 108.1676538264
Perimeter: p = 60
Semiperimeter: s = 30

Angle ∠ A = α = 27.03215621153° = 27°1'54″ = 0.47217897609 rad
Angle ∠ B = β = 31.00327191339° = 31°10″ = 0.5411099526 rad
Angle ∠ C = γ = 121.9665718751° = 121°57'57″ = 2.12987033668 rad

Height: ha = 14.42222051019
Height: hb = 12.72554750899
Height: hc = 7.72661813046

Median: ma = 21.91546070008
Median: mb = 20.79106228863
Median: mc = 7.81102496759

Inradius: r = 3.60655512755
Circumradius: R = 16.50223308377

Vertex coordinates: A[28; 0] B[0; 0] C[12.85771428571; 7.72661813046]
Centroid: CG[13.6199047619; 2.57553937682]
Coordinates of the circumscribed circle: U[14; -8.73765280905]
Coordinates of the inscribed circle: I[13; 3.60655512755]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 152.9688437885° = 152°58'6″ = 0.47217897609 rad
∠ B' = β' = 148.9977280866° = 148°59'50″ = 0.5411099526 rad
∠ C' = γ' = 58.03442812492° = 58°2'3″ = 2.12987033668 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.