# 9 28 30 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 28   c = 30

Area: T = 125.6965813375
Perimeter: p = 67
Semiperimeter: s = 33.5

Angle ∠ A = α = 17.41441079606° = 17°24'51″ = 0.30439335202 rad
Angle ∠ B = β = 68.60438134618° = 68°36'14″ = 1.19773624243 rad
Angle ∠ C = γ = 93.98220785776° = 93°58'55″ = 1.6440296709 rad

Height: ha = 27.93224029722
Height: hb = 8.97882723839
Height: hc = 8.38797208917

Median: ma = 28.66661821664
Median: mb = 17.16110023017
Median: mc = 14.40548602909

Inradius: r = 3.75221138321
Circumradius: R = 15.0366300329

Vertex coordinates: A[30; 0] B[0; 0] C[3.28333333333; 8.38797208917]
Centroid: CG[11.09444444444; 2.79332402972]
Coordinates of the circumscribed circle: U[15; -1.04441875228]
Coordinates of the inscribed circle: I[5.5; 3.75221138321]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 162.5865892039° = 162°35'9″ = 0.30439335202 rad
∠ B' = β' = 111.3966186538° = 111°23'46″ = 1.19773624243 rad
∠ C' = γ' = 86.01879214224° = 86°1'5″ = 1.6440296709 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.