# 13 23 28 triangle

### Obtuse scalene triangle.

Sides: a = 13   b = 23   c = 28

Area: T = 147.9465936071
Perimeter: p = 64
Semiperimeter: s = 32

Angle ∠ A = α = 27.35222309309° = 27°21'8″ = 0.47773864875 rad
Angle ∠ B = β = 54.37992372234° = 54°22'45″ = 0.94990967343 rad
Angle ∠ C = γ = 98.26985318457° = 98°16'7″ = 1.71551094318 rad

Height: ha = 22.76109132417
Height: hb = 12.86548640062
Height: hc = 10.56875668622

Median: ma = 24.78440674628
Median: mb = 18.55439753153
Median: mc = 12.36993168769

Inradius: r = 4.62333105022
Circumradius: R = 14.14770597678

Vertex coordinates: A[28; 0] B[0; 0] C[7.57114285714; 10.56875668622]
Centroid: CG[11.85771428571; 3.52325222874]
Coordinates of the circumscribed circle: U[14; -2.035452699]
Coordinates of the inscribed circle: I[9; 4.62333105022]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 152.6487769069° = 152°38'52″ = 0.47773864875 rad
∠ B' = β' = 125.6210762777° = 125°37'15″ = 0.94990967343 rad
∠ C' = γ' = 81.73114681543° = 81°43'53″ = 1.71551094318 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.