# 8 15 18 triangle

### Obtuse scalene triangle.

Sides: a = 8   b = 15   c = 18

Area: T = 59.35985503529
Perimeter: p = 41
Semiperimeter: s = 20.5

Angle ∠ A = α = 26.08442927774° = 26°5'3″ = 0.4555256792 rad
Angle ∠ B = β = 55.53301685755° = 55°31'49″ = 0.96991842758 rad
Angle ∠ C = γ = 98.38655386471° = 98°23'8″ = 1.71771515857 rad

Height: ha = 14.84396375882
Height: hb = 7.91444733804
Height: hc = 6.59553944837

Median: ma = 16.07879351908
Median: mb = 11.73766945943
Median: mc = 7.96986887253

Inradius: r = 2.89655390416
Circumradius: R = 9.09772572071

Vertex coordinates: A[18; 0] B[0; 0] C[4.52877777778; 6.59553944837]
Centroid: CG[7.50992592593; 2.19884648279]
Coordinates of the circumscribed circle: U[9; -1.32766833427]
Coordinates of the inscribed circle: I[5.5; 2.89655390416]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 153.9165707223° = 153°54'57″ = 0.4555256792 rad
∠ B' = β' = 124.4769831424° = 124°28'11″ = 0.96991842758 rad
∠ C' = γ' = 81.61444613529° = 81°36'52″ = 1.71771515857 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.