Explanation for Question 33 From the Math (Calc) Section on the 2019 May Sat
So question 33 says the equation X plus X squared, 2 plus Y plus three squared equals 121 defines 3 a circle in the X, Y plane. What is the radius of the circle? 4 So to find the answer to this, we're going to need to use the 5 circle formula, and that can be written out as X minus 6 H squared. So X minus H squared plus 7 Y minus K squared equals 8 R squared. So we're trying to find the radius. 9 All we really have to do is look to the right side of the 10 equation to this 121 and set that equal to R squared. 11 So we have 1 21 is equal to R squared. 12 Now, when you read both sides, you get 11 is equal to R. 13 Now negative 11 is also a square root of 121, 14 but there can't be a negative radius. 15 So that's why the answer has to be positive 11.