# 4 27 30 triangle

### Obtuse scalene triangle.

Sides: a = 4   b = 27   c = 30

Area: T = 37.60990082294
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 5.32882629454° = 5°19'42″ = 0.09329957318 rad
Angle ∠ B = β = 38.81656606129° = 38°48'56″ = 0.6777461079 rad
Angle ∠ C = γ = 135.8566076442° = 135°51'22″ = 2.37111358427 rad

Height: ha = 18.80545041147
Height: hb = 2.78658524614
Height: hc = 2.50772672153

Median: ma = 28.4699281691
Median: mb = 16.60657219054
Median: mc = 12.14549578015

Inradius: r = 1.2333082237
Circumradius: R = 21.53773932505

Vertex coordinates: A[30; 0] B[0; 0] C[3.11766666667; 2.50772672153]
Centroid: CG[11.03988888889; 0.83657557384]
Coordinates of the circumscribed circle: U[15; -15.45550738603]
Coordinates of the inscribed circle: I[3.5; 1.2333082237]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 174.6721737055° = 174°40'18″ = 0.09329957318 rad
∠ B' = β' = 141.1844339387° = 141°11'4″ = 0.6777461079 rad
∠ C' = γ' = 44.14439235583° = 44°8'38″ = 2.37111358427 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    