# 4 5 7 triangle

### Obtuse scalene triangle.

Sides: a = 4   b = 5   c = 7

Area: T = 9.79879589711
Perimeter: p = 16
Semiperimeter: s = 8

Angle ∠ A = α = 34.048773237° = 34°2'52″ = 0.59442450327 rad
Angle ∠ B = β = 44.41553085972° = 44°24'55″ = 0.77551933733 rad
Angle ∠ C = γ = 101.5376959033° = 101°32'13″ = 1.77221542476 rad

Height: ha = 4.89989794856
Height: hb = 3.91991835885
Height: hc = 2.79994168489

Median: ma = 5.74545626465
Median: mb = 5.1233475383
Median: mc = 2.87222813233

Inradius: r = 1.22547448714
Circumradius: R = 3.57221725416

Vertex coordinates: A[7; 0] B[0; 0] C[2.85771428571; 2.79994168489]
Centroid: CG[3.28657142857; 0.93331389496]
Coordinates of the circumscribed circle: U[3.5; -0.71444345083]
Coordinates of the inscribed circle: I[3; 1.22547448714]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 145.952226763° = 145°57'8″ = 0.59442450327 rad
∠ B' = β' = 135.5854691403° = 135°35'5″ = 0.77551933733 rad
∠ C' = γ' = 78.46330409672° = 78°27'47″ = 1.77221542476 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.