# 5 11 15 triangle

### Obtuse scalene triangle.

Sides: a = 5   b = 11   c = 15

Area: T = 19.13660262333
Perimeter: p = 31
Semiperimeter: s = 15.5

Angle ∠ A = α = 13.41220116047° = 13°24'43″ = 0.23440837618 rad
Angle ∠ B = β = 30.6833417109° = 30°41' = 0.53655266543 rad
Angle ∠ C = γ = 135.9054571286° = 135°54'16″ = 2.37219822375 rad

Height: ha = 7.65444104933
Height: hb = 3.4799277497
Height: hc = 2.55114701644

Median: ma = 12.91331715701
Median: mb = 9.7343961167
Median: mc = 4.09326763859

Inradius: r = 1.23545823376
Circumradius: R = 10.7788099773

Vertex coordinates: A[15; 0] B[0; 0] C[4.3; 2.55114701644]
Centroid: CG[6.43333333333; 0.85504900548]
Coordinates of the circumscribed circle: U[7.5; -7.74106352915]
Coordinates of the inscribed circle: I[4.5; 1.23545823376]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 166.5887988395° = 166°35'17″ = 0.23440837618 rad
∠ B' = β' = 149.3176582891° = 149°19' = 0.53655266543 rad
∠ C' = γ' = 44.09554287137° = 44°5'44″ = 2.37219822375 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.