three circles are manually tangent externally. their centers form a triangle whose sides are of length 8, 9, 13. find the total area of the three circles

1 answer

If the radii of the circles are x,y,z then each side of the triangle is the sum of two of the radii. So,

x+y=8
x+z=9
y+z=13
(x,y,z) = (2,6,7)

Since the area of a circle is πr^2, the area of all of the circles is
π(2^2+6^2+7^2) = 89π