# 10 11 18 triangle

### Obtuse scalene triangle.

Sides: a = 10   b = 11   c = 18

Area: T = 48.6599768518
Perimeter: p = 39
Semiperimeter: s = 19.5

Angle ∠ A = α = 29.44001972368° = 29°24'1″ = 0.51331302425 rad
Angle ∠ B = β = 32.68334637577° = 32°41' = 0.57704340535 rad
Angle ∠ C = γ = 117.9166339005° = 117°54'59″ = 2.05880283575 rad

Height: ha = 9.72199537036
Height: hb = 8.83663215487
Height: hc = 5.43999742798

Median: ma = 14.05334693226
Median: mb = 13.48114687627
Median: mc = 5.43113902456

Inradius: r = 2.49222958214
Circumradius: R = 10.18552336975

Vertex coordinates: A[18; 0] B[0; 0] C[8.41766666667; 5.43999742798]
Centroid: CG[8.80655555556; 1.87999914266]
Coordinates of the circumscribed circle: U[9; -4.76985412311]
Coordinates of the inscribed circle: I[8.5; 2.49222958214]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 150.6599802763° = 150°35'59″ = 0.51331302425 rad
∠ B' = β' = 147.3176536242° = 147°19' = 0.57704340535 rad
∠ C' = γ' = 62.08436609946° = 62°5'1″ = 2.05880283575 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.