# 7 17 20 triangle

### Obtuse scalene triangle.

Sides: a = 7   b = 17   c = 20

Area: T = 57.44656264654
Perimeter: p = 44
Semiperimeter: s = 22

Angle ∠ A = α = 19.75499227956° = 19°45' = 0.34547011798 rad
Angle ∠ B = β = 55.1550095421° = 55°9' = 0.96325507479 rad
Angle ∠ C = γ = 105.1099981783° = 105°6' = 1.83443407259 rad

Height: ha = 16.4133036133
Height: hb = 6.75883089959
Height: hc = 5.74545626465

Median: ma = 18.22877261336
Median: mb = 12.33989626793
Median: mc = 8.30766238629

Inradius: r = 2.61111648393
Circumradius: R = 10.35876205294

Vertex coordinates: A[20; 0] B[0; 0] C[4; 5.74545626465]
Centroid: CG[8; 1.91548542155]
Coordinates of the circumscribed circle: U[10; -2.69882036673]
Coordinates of the inscribed circle: I[5; 2.61111648393]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 160.2550077204° = 160°15' = 0.34547011798 rad
∠ B' = β' = 124.8549904579° = 124°51' = 0.96325507479 rad
∠ C' = γ' = 74.99000182166° = 74°54' = 1.83443407259 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.