# 7 12 13 triangle

### Acute scalene triangle.

Sides: a = 7   b = 12   c = 13

Area: T = 41.56992193817
Perimeter: p = 32
Semiperimeter: s = 16

Angle ∠ A = α = 32.2044227504° = 32°12'15″ = 0.5622069803 rad
Angle ∠ B = β = 66.00989831978° = 66°32″ = 1.15220740927 rad
Angle ∠ C = γ = 81.78767892983° = 81°47'12″ = 1.42774487579 rad

Height: ha = 11.87769198233
Height: hb = 6.92882032303
Height: hc = 6.39552645203

Median: ma = 12.01104121495
Median: mb = 8.54440037453
Median: mc = 7.36554599313

Inradius: r = 2.59880762114
Circumradius: R = 6.5677359312

Vertex coordinates: A[13; 0] B[0; 0] C[2.84661538462; 6.39552645203]
Centroid: CG[5.28220512821; 2.13217548401]
Coordinates of the circumscribed circle: U[6.5; 0.93881941874]
Coordinates of the inscribed circle: I[4; 2.59880762114]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 147.7965772496° = 147°47'45″ = 0.5622069803 rad
∠ B' = β' = 113.9911016802° = 113°59'28″ = 1.15220740927 rad
∠ C' = γ' = 98.21332107017° = 98°12'48″ = 1.42774487579 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.