# 4 11 13 triangle

### Obtuse scalene triangle.

Sides: a = 4   b = 11   c = 13

Area: T = 20.49439015319
Perimeter: p = 28
Semiperimeter: s = 14

Angle ∠ A = α = 16.65661861814° = 16°39'22″ = 0.29107052897 rad
Angle ∠ B = β = 52.02201275551° = 52°1'12″ = 0.90879225031 rad
Angle ∠ C = γ = 111.3243686263° = 111°19'25″ = 1.94329648608 rad

Height: ha = 10.2476950766
Height: hb = 3.72661639149
Height: hc = 3.1532907928

Median: ma = 11.8744342087
Median: mb = 7.8989866919
Median: mc = 5.1233475383

Inradius: r = 1.46438501094
Circumradius: R = 6.97876855216

Vertex coordinates: A[13; 0] B[0; 0] C[2.46215384615; 3.1532907928]
Centroid: CG[5.15438461538; 1.05109693093]
Coordinates of the circumscribed circle: U[6.5; -2.53773401897]
Coordinates of the inscribed circle: I[3; 1.46438501094]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 163.3443813819° = 163°20'38″ = 0.29107052897 rad
∠ B' = β' = 127.9879872445° = 127°58'48″ = 0.90879225031 rad
∠ C' = γ' = 68.67663137365° = 68°40'35″ = 1.94329648608 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.