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smc

geometry senior

Problem

A circle with center is tangent to the coordinate axes and to the hypotenuse of the -- triangle as shown, where . To the nearest hundredth, what is the radius of the circle?
problem
(A)
(B)
(C)
(D)
Solution
Draw radii and to the axes, and label the point of tangency to triangle point . Let the radius of the circle be . Square has side length . Because and are tangents from a common point , . Similarly, , and we can write: Equating the radii lengths, we have This means by the 30-60-90 triangle. Therefore, , and we get The radius of the circle is , which is Using decimal approximations, , and the answer is .
Final answer
D