# 7 7 8 triangle

### Acute isosceles triangle.

Sides: a = 7   b = 7   c = 8

Area: T = 22.97882505862
Perimeter: p = 22
Semiperimeter: s = 11

Angle ∠ A = α = 55.1550095421° = 55°9' = 0.96325507479 rad
Angle ∠ B = β = 55.1550095421° = 55°9' = 0.96325507479 rad
Angle ∠ C = γ = 69.76998091581° = 69°41'59″ = 1.21664911578 rad

Height: ha = 6.56552144532
Height: hb = 6.56552144532
Height: hc = 5.74545626465

Median: ma = 6.65220673478
Median: mb = 6.65220673478
Median: mc = 5.74545626465

Inradius: r = 2.08989318715
Circumradius: R = 4.26549025709

Vertex coordinates: A[8; 0] B[0; 0] C[4; 5.74545626465]
Centroid: CG[4; 1.91548542155]
Coordinates of the circumscribed circle: U[4; 1.48796600756]
Coordinates of the inscribed circle: I[4; 2.08989318715]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 124.8549904579° = 124°51' = 0.96325507479 rad
∠ B' = β' = 124.8549904579° = 124°51' = 0.96325507479 rad
∠ C' = γ' = 110.3300190842° = 110°18'1″ = 1.21664911578 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.