A student uses a calculator to find an answer but instead of pressing the $x^{2}$ key presses the $\sqrt{x}$ key by mistake. The student's answer was 9 . What should the answer have been?
(A) 243
(B) 81
(C) 729
(D) 3
(E) 6561
A student uses a calculator to find an answer but instead of pressing the $x^{2}$ key presses the $\sqrt{x}$ key by mistake. The student's answer was 9 . What should the answer have been?
(A) 243
(B) 81
(C) 729
(D) 3
(E) 6561

Solution 1

Since $\sqrt{x}=9, x=81$.

Thus, $x^{2}=81^{2}=6561$.

## Solution 2

Since the square root of the number entered is 9 , the number must have been 81 . The answer desired is $81^{2}=6561$.

ANSWER: (E)