Answer:
(A) Square root of 65
Explanation:
We can use Pythagorean Theorem for this, as a^2 + b^2 = c^2, that means:
4^2 + 7^2 = x^2, so 16 + 49 = x^2, add 16 and 49 and you get 65. Remember though, x was squared, so we have to find the square root of 65. Making it the square root of 65 or (A) the answer.