# Triangle calculator VC

Please enter the coordinates of the three vertices

### Obtuse scalene triangle.

Sides: a = 18.38547763109   b = 7.21111025509   c = 11.4021754251

Area: T = 13
Perimeter: p = 36.99876331128
Semiperimeter: s = 18.49988165564

Angle ∠ A = α = 161.5655051177° = 161°33'54″ = 2.82198420992 rad
Angle ∠ B = β = 7.12550163489° = 7°7'30″ = 0.12443549945 rad
Angle ∠ C = γ = 11.3109932474° = 11°18'36″ = 0.19773955598 rad

Height: ha = 1.41442135624
Height: hb = 3.60655512755
Height: hc = 2.28803508502

Median: ma = 2.55495097568
Median: mb = 14.86660687473
Median: mc = 12.7487548784

Inradius: r = 0.70327476574
Circumradius: R = 29.06988837075

Vertex coordinates: A[-2; -5] B[-9; 4] C[4; -9]
Centroid: CG[-2.33333333333; -3.33333333333]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[5.62219812593; 0.70327476574]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 18.43549488229° = 18°26'6″ = 2.82198420992 rad
∠ B' = β' = 172.8754983651° = 172°52'30″ = 0.12443549945 rad
∠ C' = γ' = 168.6990067526° = 168°41'24″ = 0.19773955598 rad

# How did we calculate this triangle?

### 1. We compute side a from coordinates using the Pythagorean theorem ### 2. We compute side b from coordinates using the Pythagorean theorem ### 3. We compute side c from coordinates using the Pythagorean theorem 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. ### 4. The triangle circumference is the sum of the lengths of its three sides ### 5. Semiperimeter of the triangle ### 6. The triangle area using Heron's formula ### 7. Calculate the heights of the triangle from its area. ### 8. Calculation of the inner angles of the triangle using a Law of Cosines    