# 9 30 30 triangle

### Acute isosceles triangle.

Sides: a = 9   b = 30   c = 30

Area: T = 133.473260955
Perimeter: p = 69
Semiperimeter: s = 34.5

Angle ∠ A = α = 17.25438531174° = 17°15'14″ = 0.30111365456 rad
Angle ∠ B = β = 81.37330734413° = 81°22'23″ = 1.4220228054 rad
Angle ∠ C = γ = 81.37330734413° = 81°22'23″ = 1.4220228054 rad

Height: ha = 29.66105798999
Height: hb = 8.898817397
Height: hc = 8.898817397

Median: ma = 29.66105798999
Median: mb = 16.29441707368
Median: mc = 16.29441707368

Inradius: r = 3.86987712913
Circumradius: R = 15.17216521227

Vertex coordinates: A[30; 0] B[0; 0] C[1.35; 8.898817397]
Centroid: CG[10.45; 2.966605799]
Coordinates of the circumscribed circle: U[15; 2.27657478184]
Coordinates of the inscribed circle: I[4.5; 3.86987712913]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 162.7466146883° = 162°44'46″ = 0.30111365456 rad
∠ B' = β' = 98.62769265587° = 98°37'37″ = 1.4220228054 rad
∠ C' = γ' = 98.62769265587° = 98°37'37″ = 1.4220228054 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.