Problem 6 A light is placed 5 ft. from the center of the globe 3 ft. in diameter. Find the area of the illuminated portion.

Solution 6

$5(1.5 - h) = 1.5^2$

$7.5 - 5h = 2.25$

$5h = 5.25$

$h = 1.05 ~ \text{ft}$

$A_z = 2\pi rh$

$A_z = 2\pi (1.5)(1.05)$

$A_z = 9.8960 ~ \text{ft.}^2$ answer

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