# 9 13 15 triangle

### Acute scalene triangle.

Sides: a = 9   b = 13   c = 15

Area: T = 58.16551742884
Perimeter: p = 37
Semiperimeter: s = 18.5

Angle ∠ A = α = 36.62443415398° = 36°37'28″ = 0.63992153462 rad
Angle ∠ B = β = 59.50987077655° = 59°30'31″ = 1.03986228841 rad
Angle ∠ C = γ = 83.86769506947° = 83°52'1″ = 1.46437544232 rad

Height: ha = 12.92655942863
Height: hb = 8.94884883521
Height: hc = 7.75553565718

Median: ma = 13.29547358003
Median: mb = 10.52437825899
Median: mc = 8.29215619759

Inradius: r = 3.1444063475
Circumradius: R = 7.54331734774

Vertex coordinates: A[15; 0] B[0; 0] C[4.56766666667; 7.75553565718]
Centroid: CG[6.52222222222; 2.58551188573]
Coordinates of the circumscribed circle: U[7.5; 0.80658946023]
Coordinates of the inscribed circle: I[5.5; 3.1444063475]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.376565846° = 143°22'32″ = 0.63992153462 rad
∠ B' = β' = 120.4911292234° = 120°29'29″ = 1.03986228841 rad
∠ C' = γ' = 96.13330493053° = 96°7'59″ = 1.46437544232 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.