Your answer to this question is definitely C!
The triangle is an isosceles triangle so that means the base angles must be congruent.
The sum of the interior angles of a triangle add up to 180 degrees.
Subtract 52 degrees from 180 degrees.
180 - 52 = 128
Divide 128 degrees by 2.
128/2 = 64
m∠X = 64°
In this case, you just multiply the expression under the root that gave the greatest integer (as you pull the square root of that number). See how I did: 4 multiplied by 31, which gives 124 then pull out the square root of 4, because 31 can not be, because it is a prime number and root would be an irrational number.