# Triangle calculator SSS - result

Please enter the triangle sides:

### Acute isosceles triangle.

Sides: a = 6   b = 18   c = 18

Area: T = 53.24547180479
Perimeter: p = 42
Semiperimeter: s = 21

Angle ∠ A = α = 19.18881364537° = 19°11'17″ = 0.33548961584 rad
Angle ∠ B = β = 80.40659317731° = 80°24'21″ = 1.40333482476 rad
Angle ∠ C = γ = 80.40659317731° = 80°24'21″ = 1.40333482476 rad

Height: ha = 17.74882393493
Height: hb = 5.91660797831
Height: hc = 5.91660797831

Median: ma = 17.74882393493
Median: mb = 9.95498743711
Median: mc = 9.95498743711

Inradius: r = 2.53554627642
Circumradius: R = 9.12876659511

Vertex coordinates: A[18; 0] B[0; 0] C[1; 5.91660797831]
Centroid: CG[6.33333333333; 1.97220265944]
Coordinates of the circumscribed circle: U[9; 1.52112776585]
Coordinates of the inscribed circle: I[3; 2.53554627642]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 160.8121863546° = 160°48'43″ = 0.33548961584 rad
∠ B' = β' = 99.59440682269° = 99°35'39″ = 1.40333482476 rad
∠ C' = γ' = 99.59440682269° = 99°35'39″ = 1.40333482476 rad

# How did we calculate this triangle?

### 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    