Explanation for Question 6 From the Math (Calc) Section on the 2018 May Sat
Question six says the area enclosed by circle is 25 PI square inches. 2 What is the length in inches of the radius of the circle? 3 So the equation for the area of the circle is PI R squared. 4 So we're going to take that and set that equal to 25 PI to 5 solve for R so 25 PI is equal to PI R squared. 6 The PIs cancel. So that gives us 25 is equal to R squared. 7 And then we can square root, both sides to get R is equal to 8 five, which is answer choice B.