# 9 20 25 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 20   c = 25

Area: T = 82.48663625092
Perimeter: p = 54
Semiperimeter: s = 27

Angle ∠ A = α = 19.26554645654° = 19°15'56″ = 0.33662457886 rad
Angle ∠ B = β = 47.15663569564° = 47°9'23″ = 0.82330336921 rad
Angle ∠ C = γ = 113.5788178478° = 113°34'41″ = 1.98223131729 rad

Height: ha = 18.33303027798
Height: hb = 8.24986362509
Height: hc = 6.59989090007

Median: ma = 22.18767077323
Median: mb = 15.90659737206
Median: mc = 9.17987798753

Inradius: r = 3.05550504633
Circumradius: R = 13.63986181397

Vertex coordinates: A[25; 0] B[0; 0] C[6.12; 6.59989090007]
Centroid: CG[10.37333333333; 2.21996363336]
Coordinates of the circumscribed circle: U[12.5; -5.45554472559]
Coordinates of the inscribed circle: I[7; 3.05550504633]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 160.7354535435° = 160°44'4″ = 0.33662457886 rad
∠ B' = β' = 132.8443643044° = 132°50'37″ = 0.82330336921 rad
∠ C' = γ' = 66.42218215218° = 66°25'19″ = 1.98223131729 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.