# 11 12 13 triangle

### Acute scalene triangle.

Sides: a = 11   b = 12   c = 13

Area: T = 61.48217045958
Perimeter: p = 36
Semiperimeter: s = 18

Angle ∠ A = α = 52.02201275551° = 52°1'12″ = 0.90879225031 rad
Angle ∠ B = β = 59.30435587083° = 59°18'13″ = 1.03550423576 rad
Angle ∠ C = γ = 68.67663137365° = 68°40'35″ = 1.19986277928 rad

Height: ha = 11.17884917447
Height: hb = 10.2476950766
Height: hc = 9.4598723784

Median: ma = 11.23661025271
Median: mb = 10.44403065089
Median: mc = 9.5

Inradius: r = 3.41656502553
Circumradius: R = 6.97876855216

Vertex coordinates: A[13; 0] B[0; 0] C[5.61553846154; 9.4598723784]
Centroid: CG[6.20551282051; 3.1532907928]
Coordinates of the circumscribed circle: U[6.5; 2.53773401897]
Coordinates of the inscribed circle: I[6; 3.41656502553]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 127.9879872445° = 127°58'48″ = 0.90879225031 rad
∠ B' = β' = 120.6966441292° = 120°41'47″ = 1.03550423576 rad
∠ C' = γ' = 111.3243686263° = 111°19'25″ = 1.19986277928 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.