The hoop on the stair case
Level
pending
A hoop is resting vertically at stair case as shown . AB = 12 cm and BC= 8 cm. What is the radius of the hoop ?
The answer is 13.
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1 solution
Let r be the radius of the hoop. Then using Pythagoras Theorem we get
r^2 = (r-8)^2 + 12^2
r^2 = r^2 + 64 - 16r + 144
208 = 16r
r = 13