# 11 21 23 triangle

### Acute scalene triangle.

Sides: a = 11   b = 21   c = 23

Area: T = 115.2054980361
Perimeter: p = 55
Semiperimeter: s = 27.5

Angle ∠ A = α = 28.49222090409° = 28°29'32″ = 0.49772828589 rad
Angle ∠ B = β = 65.60438347173° = 65°36'14″ = 1.14550029178 rad
Angle ∠ C = γ = 85.90439562418° = 85°54'14″ = 1.49993068769 rad

Height: ha = 20.94663600657
Height: hb = 10.97219028915
Height: hc = 10.01878243792

Median: ma = 21.32548681121
Median: mb = 14.65443508898
Median: mc = 12.19663109177

Inradius: r = 4.18992720131
Circumradius: R = 11.5299449472

Vertex coordinates: A[23; 0] B[0; 0] C[4.54334782609; 10.01878243792]
Centroid: CG[9.18111594203; 3.33992747931]
Coordinates of the circumscribed circle: U[11.5; 0.82435321051]
Coordinates of the inscribed circle: I[6.5; 4.18992720131]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 151.5087790959° = 151°30'28″ = 0.49772828589 rad
∠ B' = β' = 114.3966165283° = 114°23'46″ = 1.14550029178 rad
∠ C' = γ' = 94.09660437582° = 94°5'46″ = 1.49993068769 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.