# 7 12 15 triangle

### Obtuse scalene triangle.

Sides: a = 7   b = 12   c = 15

Area: T = 41.23110562562
Perimeter: p = 34
Semiperimeter: s = 17

Angle ∠ A = α = 27.26660444507° = 27°15'58″ = 0.47658822497 rad
Angle ∠ B = β = 51.75333801217° = 51°45'12″ = 0.90332668822 rad
Angle ∠ C = γ = 100.9810575428° = 100°58'50″ = 1.76224435218 rad

Height: ha = 11.78803017875
Height: hb = 6.87218427094
Height: hc = 5.49774741675

Median: ma = 13.12444047484
Median: mb = 10.05498756211
Median: mc = 6.34442887702

Inradius: r = 2.42553562504
Circumradius: R = 7.64398721886

Vertex coordinates: A[15; 0] B[0; 0] C[4.33333333333; 5.49774741675]
Centroid: CG[6.44444444444; 1.83224913892]
Coordinates of the circumscribed circle: U[7.5; -1.45552137502]
Coordinates of the inscribed circle: I[5; 2.42553562504]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 152.7343955549° = 152°44'2″ = 0.47658822497 rad
∠ B' = β' = 128.2476619878° = 128°14'48″ = 0.90332668822 rad
∠ C' = γ' = 79.01994245724° = 79°1'10″ = 1.76224435218 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.