Half of the square root of a number is 1 . The number is
(A) 2
(B) 4
(C) 8
(D) 9
(E) 16
Solution 1

Since half the square root of the number is one, then the square root of the number must be 2 .

Since the square root of 4 is equal to 2 , then the unknown number is 4 .

## Solution 2

Let the unknown number be $x$.

Since one half the square root of $x$ is one, then $\frac{1}{2} \sqrt{x}=1$.

Multiplying both sides of the equation by 2 gives, $2 \times \frac{1}{2} \sqrt{x}=1 \times 2$ or $\sqrt{x}=2$.

Squaring both sides of the equation gives, $(\sqrt{x})^{2}=2^{2}$ or $x=4$.

ANSWER: (B)