Explanation for Question 20 From the Math (No Calc) Section on the 2018 April Sat
Question 20 says segments oh eight and O our radius of the 2 semicircle above arc, a B has length three PI and oh 3 eight is equal to five. What is the value of X? 4 So I've gone ahead and filled in on this picture, 5 up here, the information we know, we know that the arc length is equal 6 to three PI, and we know that this radius is equal to five. 7 So to figure out what the angle degree is, 8 we're going to use this equation that I've written right down here, 9 X over 360 times, two PI R finds you the arc length. 10 So since we know the radius and the arc length, 11 we can just plug that into this equation and solve for X. 12 So we have X over 360 times, 13 two PI R, which is two times PI times five or just 10 PI 14 is equal to three PI. 15 So first we can divide both sides by 10 pie, 16 and we're going to get three over 10 on the right side. 17 So X over 360 is equal 18 to three over 10, then we can cross multiply. 19 So 10 X is equal to 1080, 20 and then we can divide both sides by 10 and get X is equal 21 to 108. 22 And that is the correct answer to this question.
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