Bunuel

Three carpet pieces—in the shapes of a square, a triangle, and a semicircle—are attached to one another, as shown in the figure above, to cover the floor of a room. If the area of the square is 144 feet and the perimeter of the triangle is 28 feet, what is the perimeter of the room’s floor, in feet?
(A) \(32+12π\)
(B) \(40+6π\)
(C) \(34+12π\)
(D) \(52+6π\)
(E) \(52+12π\)
Project PS Butler
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Solution: Firstly, the area if the given
square = 144.
Let us assume the side of the square be 'a'. Then we can write \(a^2=144\)
\(⇒ a=\sqrt{144}\)
\(⇒ a=12\)
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Now lets us concentrate on the
triangle.
The perimeter of the triangle is 28. This includes side 12 as well. so the sum of the other 2 sides (say a and b) is \(28-12=16\).
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Now lets us concentrate on the
Semi Circle.
The diameter of semi-circle = 12. Thus radius \(= \frac{12}{2}=6\).
So, the length of boundary or circumference \(= \pi \times r = \pi \times 6=6\pi\)
Ultimately the perimeter of whole figure \(= 12 + a + b + 12 + 6\pi \)
\(= 12 + 16 +12+ 6\pi\)
\(= 40+6\pi \)
Hence the right answer is
Option B.
12 = Just 1 side of the square-shaped part of the carpet.