# 17 21 25 triangle

### Acute scalene triangle.

Sides: a = 17   b = 21   c = 25

Area: T = 176.5599303068
Perimeter: p = 63
Semiperimeter: s = 31.5

Angle ∠ A = α = 42.26985844296° = 42°16'7″ = 0.73877259685 rad
Angle ∠ B = β = 56.18879349057° = 56°11'17″ = 0.9810664464 rad
Angle ∠ C = γ = 81.54334806647° = 81°32'37″ = 1.42332022211 rad

Height: ha = 20.77216827139
Height: hb = 16.81551717208
Height: hc = 14.12547442455

Median: ma = 21.46550879337
Median: mb = 18.62112244495
Median: mc = 14.44881832768

Inradius: r = 5.60550572403
Circumradius: R = 12.63773969608

Vertex coordinates: A[25; 0] B[0; 0] C[9.46; 14.12547442455]
Centroid: CG[11.48766666667; 4.70882480818]
Coordinates of the circumscribed circle: U[12.5; 1.85884407295]
Coordinates of the inscribed circle: I[10.5; 5.60550572403]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 137.731141557° = 137°43'53″ = 0.73877259685 rad
∠ B' = β' = 123.8122065094° = 123°48'43″ = 0.9810664464 rad
∠ C' = γ' = 98.45765193353° = 98°27'23″ = 1.42332022211 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.