# 7 9 9 triangle

### Acute isosceles triangle.

Sides: a = 7   b = 9   c = 9

Area: T = 29.02204669156
Perimeter: p = 25
Semiperimeter: s = 12.5

Angle ∠ A = α = 45.77107609523° = 45°46'15″ = 0.79988504798 rad
Angle ∠ B = β = 67.11546195238° = 67°6'53″ = 1.17113710869 rad
Angle ∠ C = γ = 67.11546195238° = 67°6'53″ = 1.17113710869 rad

Height: ha = 8.29215619759
Height: hb = 6.44989926479
Height: hc = 6.44989926479

Median: ma = 8.29215619759
Median: mb = 6.69895440801
Median: mc = 6.69895440801

Inradius: r = 2.32216373532
Circumradius: R = 4.88444837822

Vertex coordinates: A[9; 0] B[0; 0] C[2.72222222222; 6.44989926479]
Centroid: CG[3.90774074074; 2.1549664216]
Coordinates of the circumscribed circle: U[4.5; 1.98995214708]
Coordinates of the inscribed circle: I[3.5; 2.32216373532]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 134.2299239048° = 134°13'45″ = 0.79988504798 rad
∠ B' = β' = 112.8855380476° = 112°53'7″ = 1.17113710869 rad
∠ C' = γ' = 112.8855380476° = 112°53'7″ = 1.17113710869 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.