# Triangle calculator - result

Please enter what you know about the triangle:
You have entered side c and aspect ratio a:b:c = 3:5:7.

### Obtuse scalene triangle.

Sides: a = 7.5   b = 12.5   c = 17.5

Area: T = 40.59549408024
Perimeter: p = 37.5
Semiperimeter: s = 18.75

Angle ∠ A = α = 21.78767892983° = 21°47'12″ = 0.38802512067 rad
Angle ∠ B = β = 38.21332107017° = 38°12'48″ = 0.66769463445 rad
Angle ∠ C = γ = 120° = 2.09443951024 rad

Height: ha = 10.82553175473
Height: hb = 6.49551905284
Height: hc = 4.6399421806

Median: ma = 14.73772826532
Median: mb = 11.92442400177
Median: mc = 5.44986236794

Inradius: r = 2.16550635095
Circumradius: R = 10.10436297108

Vertex coordinates: A[17.5; 0] B[0; 0] C[5.89328571429; 4.6399421806]
Centroid: CG[7.79876190476; 1.54664739353]
Coordinates of the circumscribed circle: U[8.75; -5.05218148554]
Coordinates of the inscribed circle: I[6.25; 2.16550635095]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 158.2133210702° = 158°12'48″ = 0.38802512067 rad
∠ B' = β' = 141.7876789298° = 141°47'12″ = 0.66769463445 rad
∠ C' = γ' = 60° = 2.09443951024 rad

# How did we calculate this triangle?

### 1. Input data entered: side c and aspect ratio a:b:c. ### 2. From angle β, angle γ and side c we calculate side b - By using the law of sines, we calculate unknown side b: ### 3. From side b we calculate T: 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 ### 9. Inradius ### 10. Circumradius ### 11. 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.