# 13 21 27 triangle

### Obtuse scalene triangle.

Sides: a = 13   b = 21   c = 27

Area: T = 133.2198570402
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 28.02882451983° = 28°1'42″ = 0.48991851623 rad
Angle ∠ B = β = 49.38331749605° = 49°22'59″ = 0.86218989981 rad
Angle ∠ C = γ = 102.5898579841° = 102°35'19″ = 1.79105084932 rad

Height: ha = 20.49551646773
Height: hb = 12.68774828954
Height: hc = 9.8688042252

Median: ma = 23.29769955144
Median: mb = 18.40551623193
Median: mc = 11.07992599031

Inradius: r = 4.36878219804
Circumradius: R = 13.83325309635

Vertex coordinates: A[27; 0] B[0; 0] C[8.4632962963; 9.8688042252]
Centroid: CG[11.82109876543; 3.28993474173]
Coordinates of the circumscribed circle: U[13.5; -3.01547823895]
Coordinates of the inscribed circle: I[9.5; 4.36878219804]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 151.9721754802° = 151°58'18″ = 0.48991851623 rad
∠ B' = β' = 130.617682504° = 130°37'1″ = 0.86218989981 rad
∠ C' = γ' = 77.41114201588° = 77°24'41″ = 1.79105084932 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.