# 10 18 20 triangle

### Acute scalene triangle.

Sides: a = 10   b = 18   c = 20

Area: T = 89.87997772826
Perimeter: p = 48
Semiperimeter: s = 24

Angle ∠ A = α = 29.92664348666° = 29°55'35″ = 0.52223148218 rad
Angle ∠ B = β = 63.89661188627° = 63°53'46″ = 1.11551976534 rad
Angle ∠ C = γ = 86.17774462707° = 86°10'39″ = 1.50440801784 rad

Height: ha = 17.96599554565
Height: hb = 9.97877530314
Height: hc = 8.98799777283

Median: ma = 18.35875597507
Median: mb = 13
Median: mc = 10.58330052443

Inradius: r = 3.74216573868
Circumradius: R = 10.02222965717

Vertex coordinates: A[20; 0] B[0; 0] C[4.4; 8.98799777283]
Centroid: CG[8.13333333333; 2.99333259094]
Coordinates of the circumscribed circle: U[10; 0.66881531048]
Coordinates of the inscribed circle: I[6; 3.74216573868]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 150.0743565133° = 150°4'25″ = 0.52223148218 rad
∠ B' = β' = 116.1043881137° = 116°6'14″ = 1.11551976534 rad
∠ C' = γ' = 93.82325537293° = 93°49'21″ = 1.50440801784 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.