# 5 7 7 triangle

### Acute isosceles triangle.

Sides: a = 5   b = 7   c = 7

Area: T = 16.34658710383
Perimeter: p = 19
Semiperimeter: s = 9.5

Angle ∠ A = α = 41.85496648553° = 41°50'59″ = 0.73304144426 rad
Angle ∠ B = β = 69.07551675724° = 69°4'31″ = 1.20655891055 rad
Angle ∠ C = γ = 69.07551675724° = 69°4'31″ = 1.20655891055 rad

Height: ha = 6.53883484153
Height: hb = 4.67702488681
Height: hc = 4.67702488681

Median: ma = 6.53883484153
Median: mb = 4.97549371855
Median: mc = 4.97549371855

Inradius: r = 1.7210618004
Circumradius: R = 3.74771236532

Vertex coordinates: A[7; 0] B[0; 0] C[1.78657142857; 4.67702488681]
Centroid: CG[2.92985714286; 1.55767496227]
Coordinates of the circumscribed circle: U[3.5; 1.33882584476]
Coordinates of the inscribed circle: I[2.5; 1.7210618004]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 138.1550335145° = 138°9'1″ = 0.73304144426 rad
∠ B' = β' = 110.9254832428° = 110°55'29″ = 1.20655891055 rad
∠ C' = γ' = 110.9254832428° = 110°55'29″ = 1.20655891055 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.