You need to use a ratio of height (H) to shadow length (L) to solve the first problem. It's basically a use of similar triangles, with two perpendicular sides, and with the shadow making the same angle with the vertical.
<span>6 ft = 72 ins, so that rH/L = 72/16 = 9/2 for the player. </span>
<span>So the bleachers are 9/2 x 6 ft = 27 ft. </span>
<span>For the second problem, 9 ft = 108 in, so that the ratio of the actual linear dimensions to the plan's linear dimensions are 9ft/(1/2in) = 2 x 108 = 216. </span>
<span>So the stage will have dimensions 216 times larger than 1.75" by 3". </span>
When there is no number between a grouping symbol and a + or - sign, by default you can multiply the contents in the group by 1 to get rid of the grouping symbols.