# Triangle calculator VC

Please enter the coordinates of the three vertices

### Obtuse isosceles triangle.

Sides: a = 10.05498756211   b = 10.05498756211   c = 15.55663491861

Area: T = 49.5
Perimeter: p = 35.65661004283
Semiperimeter: s = 17.82880502142

Angle ∠ A = α = 39.28994068625° = 39°17'22″ = 0.68657295109 rad
Angle ∠ B = β = 39.28994068625° = 39°17'22″ = 0.68657295109 rad
Angle ∠ C = γ = 101.4211186275° = 101°25'16″ = 1.77701336318 rad

Height: ha = 9.85108681831
Height: hb = 9.85108681831
Height: hc = 6.36439610307

Median: ma = 12.09333866224
Median: mb = 12.09333866224
Median: mc = 6.36439610307

Inradius: r = 2.77765234788
Circumradius: R = 7.93553094333

Vertex coordinates: A[7; -2] B[-4; 9] C[-3; -1]
Centroid: CG[0; 2]
Coordinates of the circumscribed circle: U[0; 0]
Coordinates of the inscribed circle: I[3.39435286963; 2.77765234788]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 140.7110593137° = 140°42'38″ = 0.68657295109 rad
∠ B' = β' = 140.7110593137° = 140°42'38″ = 0.68657295109 rad
∠ C' = γ' = 78.5798813725° = 78°34'44″ = 1.77701336318 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    