# 7 21 25 triangle

### Obtuse scalene triangle.

Sides: a = 7   b = 21   c = 25

Area: T = 65.29330892208
Perimeter: p = 53
Semiperimeter: s = 26.5

Angle ∠ A = α = 14.40327028211° = 14°24'10″ = 0.25113745854 rad
Angle ∠ B = β = 48.26328531992° = 48°15'46″ = 0.84223456947 rad
Angle ∠ C = γ = 117.334444398° = 117°20'4″ = 2.04878723734 rad

Height: ha = 18.65551683488
Height: hb = 6.21883894496
Height: hc = 5.22334471377

Median: ma = 22.82199474145
Median: mb = 15.05882203464
Median: mc = 9.42107218407

Inradius: r = 2.46438901593
Circumradius: R = 14.07111675763

Vertex coordinates: A[25; 0] B[0; 0] C[4.66; 5.22334471377]
Centroid: CG[9.88766666667; 1.74111490459]
Coordinates of the circumscribed circle: U[12.5; -6.46112504177]
Coordinates of the inscribed circle: I[5.5; 2.46438901593]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 165.5977297179° = 165°35'50″ = 0.25113745854 rad
∠ B' = β' = 131.7377146801° = 131°44'14″ = 0.84223456947 rad
∠ C' = γ' = 62.66655560203° = 62°39'56″ = 2.04878723734 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.