BTGmoderatorDC wrote: ↑Mon Sep 28, 2020 5:48 pm
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What is the area of the circle above with center O?
(1) The length of major arc CA is 27pi
(2) The perimeter of OABC is 72
OA
D
Source: Princeton Review
The Quadrilateral \(OABC\) is evidently a square as
1. \(OA = OC\)
2. \(\angle{AOC}\) is \(90^{\circ}\).
3. \(\angle{OAB}\) is \(90^{\circ}\). As tangent is perpendicular to radius (as perceived from figure)
Statement 1 gives the value of \(\pi \cdot (360-90)/360\cdot r\), from which \(r\) can be calculated. \(\Large{\color{green}\checkmark}\)
Statement 2 gives the perimeter of the square which is \(4r\) so \(r\) can be calculated. \(\Large{\color{green}\checkmark}\)
Both are independently sufficient.
Therefore,
D