# 8 9 9 triangle

### Acute isosceles triangle.

Sides: a = 8   b = 9   c = 9

Area: T = 32.24990309932
Perimeter: p = 26
Semiperimeter: s = 13

Angle ∠ A = α = 52.77655999225° = 52°46'32″ = 0.92111079834 rad
Angle ∠ B = β = 63.61222000388° = 63°36'44″ = 1.11102423351 rad
Angle ∠ C = γ = 63.61222000388° = 63°36'44″ = 1.11102423351 rad

Height: ha = 8.06222577483
Height: hb = 7.16664513318
Height: hc = 7.16664513318

Median: ma = 8.06222577483
Median: mb = 7.22884161474
Median: mc = 7.22884161474

Inradius: r = 2.48106946918
Circumradius: R = 5.02334067509

Vertex coordinates: A[9; 0] B[0; 0] C[3.55655555556; 7.16664513318]
Centroid: CG[4.18551851852; 2.38988171106]
Coordinates of the circumscribed circle: U[4.5; 2.23326252226]
Coordinates of the inscribed circle: I[4; 2.48106946918]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 127.2244400078° = 127°13'28″ = 0.92111079834 rad
∠ B' = β' = 116.3887799961° = 116°23'16″ = 1.11102423351 rad
∠ C' = γ' = 116.3887799961° = 116°23'16″ = 1.11102423351 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.