# 9 10 12 triangle

### Acute scalene triangle.

Sides: a = 9   b = 10   c = 12

Area: T = 44.03990451758
Perimeter: p = 31
Semiperimeter: s = 15.5

Angle ∠ A = α = 47.22114422911° = 47°13'17″ = 0.82441696455 rad
Angle ∠ B = β = 54.64105803778° = 54°38'26″ = 0.95436580328 rad
Angle ∠ C = γ = 78.13879773311° = 78°8'17″ = 1.36437649753 rad

Height: ha = 9.78664544835
Height: hb = 8.80878090352
Height: hc = 7.34398408626

Median: ma = 10.08771205009
Median: mb = 9.35441434669
Median: mc = 7.38224115301

Inradius: r = 2.8411228721
Circumradius: R = 6.13109231143

Vertex coordinates: A[12; 0] B[0; 0] C[5.20883333333; 7.34398408626]
Centroid: CG[5.73661111111; 2.44766136209]
Coordinates of the circumscribed circle: U[6; 1.26602453068]
Coordinates of the inscribed circle: I[5.5; 2.8411228721]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 132.7798557709° = 132°46'43″ = 0.82441696455 rad
∠ B' = β' = 125.3599419622° = 125°21'34″ = 0.95436580328 rad
∠ C' = γ' = 101.8622022669° = 101°51'43″ = 1.36437649753 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.