# 16 21 30 triangle

### Obtuse scalene triangle.

Sides: a = 16   b = 21   c = 30

Area: T = 160.1511295655
Perimeter: p = 67
Semiperimeter: s = 33.5

Angle ∠ A = α = 30.55884317859° = 30°33'30″ = 0.53333452489 rad
Angle ∠ B = β = 41.85987922056° = 41°51'32″ = 0.73105737449 rad
Angle ∠ C = γ = 107.5832776008° = 107°34'58″ = 1.87876736598 rad

Height: ha = 20.01989119569
Height: hb = 15.25325043481
Height: hc = 10.67767530437

Median: ma = 24.6277220712
Median: mb = 21.62875287539
Median: mc = 11.11330553854

Inradius: r = 4.78106356912
Circumradius: R = 15.73551209036

Vertex coordinates: A[30; 0] B[0; 0] C[11.91766666667; 10.67767530437]
Centroid: CG[13.97222222222; 3.55989176812]
Coordinates of the circumscribed circle: U[15; -4.7533317773]
Coordinates of the inscribed circle: I[12.5; 4.78106356912]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 149.4421568214° = 149°26'30″ = 0.53333452489 rad
∠ B' = β' = 138.1411207794° = 138°8'28″ = 0.73105737449 rad
∠ C' = γ' = 72.41772239916° = 72°25'2″ = 1.87876736598 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.