# 5 7 9 triangle

### Obtuse scalene triangle.

Sides: a = 5   b = 7   c = 9

Area: T = 17.41222801494
Perimeter: p = 21
Semiperimeter: s = 10.5

Angle ∠ A = α = 33.55773097619° = 33°33'26″ = 0.58656855435 rad
Angle ∠ B = β = 50.70435197608° = 50°42'13″ = 0.88549433622 rad
Angle ∠ C = γ = 95.73991704773° = 95°44'21″ = 1.6710963748 rad

Height: ha = 6.96549120597
Height: hb = 4.97549371855
Height: hc = 3.86993955887

Median: ma = 7.66548548584
Median: mb = 6.38435726674
Median: mc = 4.09326763859

Inradius: r = 1.65883123952
Circumradius: R = 4.52326701687

Vertex coordinates: A[9; 0] B[0; 0] C[3.16766666667; 3.86993955887]
Centroid: CG[4.05655555556; 1.29897985296]
Coordinates of the circumscribed circle: U[4.5; -0.45222670169]
Coordinates of the inscribed circle: I[3.5; 1.65883123952]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.4432690238° = 146°26'34″ = 0.58656855435 rad
∠ B' = β' = 129.2966480239° = 129°17'47″ = 0.88549433622 rad
∠ C' = γ' = 84.26108295227° = 84°15'39″ = 1.6710963748 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.