What is the circumference of a circle circumscribed around a rectangle with sides 10 cm and 24 cm?

A rectangle can be split up into 2 right triangles. The hypotenuse of the right triangles is also the diagonal of the rectangle.
The diagonal is a diameter of the circle you want.
a^2 + b^2 = c^2
a = 10
b = 24
c = ???

10^2 + 24^2 = b^2
b^2 = 100 + 576
c^2 = 676
c = sqrt(676)
c = 26 The other (-) root is meaningless.
c = diameter of the circle
r = d/2 = 26/2 = 13
The radius of the circle is 13 cm

C = 2*pi*r
r = 13
pi = 3.14
C = ???

C = 2*3.14 * 13
C = 81.68 cm