# 7 12 12 triangle

### Acute isosceles triangle.

Sides: a = 7   b = 12   c = 12

Area: T = 40.17438409914
Perimeter: p = 31
Semiperimeter: s = 15.5

Angle ∠ A = α = 33.91655266° = 33°54'56″ = 0.59219376067 rad
Angle ∠ B = β = 73.04222367° = 73°2'32″ = 1.27548275234 rad
Angle ∠ C = γ = 73.04222367° = 73°2'32″ = 1.27548275234 rad

Height: ha = 11.47882402832
Height: hb = 6.69656401652
Height: hc = 6.69656401652

Median: ma = 11.47882402832
Median: mb = 7.77881745931
Median: mc = 7.77881745931

Inradius: r = 2.59218607091
Circumradius: R = 6.27327385229

Vertex coordinates: A[12; 0] B[0; 0] C[2.04216666667; 6.69656401652]
Centroid: CG[4.68105555556; 2.23218800551]
Coordinates of the circumscribed circle: U[6; 1.83295487358]
Coordinates of the inscribed circle: I[3.5; 2.59218607091]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.08444734° = 146°5'4″ = 0.59219376067 rad
∠ B' = β' = 106.95877633° = 106°57'28″ = 1.27548275234 rad
∠ C' = γ' = 106.95877633° = 106°57'28″ = 1.27548275234 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.