# 13 19 20 triangle

### Acute scalene triangle.

Sides: a = 13   b = 19   c = 20

Area: T = 119.1476968069
Perimeter: p = 52
Semiperimeter: s = 26

Angle ∠ A = α = 38.83657017687° = 38°50'9″ = 0.67878108632 rad
Angle ∠ B = β = 66.42218215218° = 66°25'19″ = 1.15992794807 rad
Angle ∠ C = γ = 74.74224767095° = 74°44'33″ = 1.30545023097 rad

Height: ha = 18.33303027798
Height: hb = 12.54217861125
Height: hc = 11.91546968069

Median: ma = 18.39215741577
Median: mb = 13.93773598648
Median: mc = 12.84552325787

Inradius: r = 4.5832575695
Circumradius: R = 10.36553497862

Vertex coordinates: A[20; 0] B[0; 0] C[5.2; 11.91546968069]
Centroid: CG[8.4; 3.97215656023]
Coordinates of the circumscribed circle: U[10; 2.72877236279]
Coordinates of the inscribed circle: I[7; 4.5832575695]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 141.1644298231° = 141°9'51″ = 0.67878108632 rad
∠ B' = β' = 113.5788178478° = 113°34'41″ = 1.15992794807 rad
∠ C' = γ' = 105.258752329° = 105°15'27″ = 1.30545023097 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.