# 10 18 18 triangle

### Acute isosceles triangle.

Sides: a = 10   b = 18   c = 18

Area: T = 86.4588082329
Perimeter: p = 46
Semiperimeter: s = 23

Angle ∠ A = α = 32.25552404263° = 32°15'19″ = 0.56329601465 rad
Angle ∠ B = β = 73.87223797868° = 73°52'21″ = 1.28993162536 rad
Angle ∠ C = γ = 73.87223797868° = 73°52'21″ = 1.28993162536 rad

Height: ha = 17.29216164658
Height: hb = 9.60664535921
Height: hc = 9.60664535921

Median: ma = 17.29216164658
Median: mb = 11.44655231423
Median: mc = 11.44655231423

Inradius: r = 3.75990470578
Circumradius: R = 9.36987018979

Vertex coordinates: A[18; 0] B[0; 0] C[2.77877777778; 9.60664535921]
Centroid: CG[6.92659259259; 3.20221511974]
Coordinates of the circumscribed circle: U[9; 2.60224171938]
Coordinates of the inscribed circle: I[5; 3.75990470578]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 147.7454759574° = 147°44'41″ = 0.56329601465 rad
∠ B' = β' = 106.1287620213° = 106°7'39″ = 1.28993162536 rad
∠ C' = γ' = 106.1287620213° = 106°7'39″ = 1.28993162536 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.