# 12 12 17 triangle

### Obtuse isosceles triangle.

Sides: a = 12   b = 12   c = 17

Area: T = 721.9995659709
Perimeter: p = 41
Semiperimeter: s = 20.5

Angle ∠ A = α = 44.90105279607° = 44°54'2″ = 0.78436620488 rad
Angle ∠ B = β = 44.90105279607° = 44°54'2″ = 0.78436620488 rad
Angle ∠ C = γ = 90.19989440786° = 90°11'56″ = 1.5744268556 rad

Height: ha = 121.9999276618
Height: hb = 121.9999276618
Height: hc = 8.4710537173

Median: ma = 13.43550288425
Median: mb = 13.43550288425
Median: mc = 8.4710537173

Inradius: r = 3.51221739498
Circumradius: R = 8.55000512399

Vertex coordinates: A[17; 0] B[0; 0] C[8.5; 8.4710537173]
Centroid: CG[8.5; 2.8243512391]
Coordinates of the circumscribed circle: U[8.5; -0.03295140668]
Coordinates of the inscribed circle: I[8.5; 3.51221739498]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 135.0999472039° = 135°5'58″ = 0.78436620488 rad
∠ B' = β' = 135.0999472039° = 135°5'58″ = 0.78436620488 rad
∠ C' = γ' = 89.80110559214° = 89°48'4″ = 1.5744268556 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.