# 2 7 7 triangle

### Acute isosceles triangle.

Sides: a = 2   b = 7   c = 7

Area: T = 6.92882032303
Perimeter: p = 16
Semiperimeter: s = 8

Angle ∠ A = α = 16.42664214035° = 16°25'35″ = 0.28766951378 rad
Angle ∠ B = β = 81.78767892983° = 81°47'12″ = 1.42774487579 rad
Angle ∠ C = γ = 81.78767892983° = 81°47'12″ = 1.42774487579 rad

Height: ha = 6.92882032303
Height: hb = 1.97994866372
Height: hc = 1.97994866372

Median: ma = 6.92882032303
Median: mb = 3.77549172176
Median: mc = 3.77549172176

Inradius: r = 0.86660254038
Circumradius: R = 3.53662703988

Vertex coordinates: A[7; 0] B[0; 0] C[0.28657142857; 1.97994866372]
Centroid: CG[2.42985714286; 0.66598288791]
Coordinates of the circumscribed circle: U[3.5; 0.50551814855]
Coordinates of the inscribed circle: I[1; 0.86660254038]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 163.5743578597° = 163°34'25″ = 0.28766951378 rad
∠ B' = β' = 98.21332107017° = 98°12'48″ = 1.42774487579 rad
∠ C' = γ' = 98.21332107017° = 98°12'48″ = 1.42774487579 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.