# 17 17 18 triangle

### Acute isosceles triangle.

Sides: a = 17   b = 17   c = 18

Area: T = 129.8799845917
Perimeter: p = 52
Semiperimeter: s = 26

Angle ∠ A = α = 58.03442812492° = 58°2'3″ = 1.01328892868 rad
Angle ∠ B = β = 58.03442812492° = 58°2'3″ = 1.01328892868 rad
Angle ∠ C = γ = 63.93114375016° = 63°55'53″ = 1.11658140799 rad

Height: ha = 15.27105701078
Height: hb = 15.27105701078
Height: hc = 14.42222051019

Median: ma = 15.3055227865
Median: mb = 15.3055227865
Median: mc = 14.42222051019

Inradius: r = 4.9922301766
Circumradius: R = 10.01992722943

Vertex coordinates: A[18; 0] B[0; 0] C[9; 14.42222051019]
Centroid: CG[9; 4.80774017006]
Coordinates of the circumscribed circle: U[9; 4.40329328075]
Coordinates of the inscribed circle: I[9; 4.9922301766]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 121.9665718751° = 121°57'57″ = 1.01328892868 rad
∠ B' = β' = 121.9665718751° = 121°57'57″ = 1.01328892868 rad
∠ C' = γ' = 116.0698562498° = 116°4'7″ = 1.11658140799 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.