# Question #7c8a4

Dec 1, 2016

$23 {\text{ft}}^{3}$

#### Explanation:

If Valerie has a calculator, she can just calculate that $\sqrt{500} \approx 22.36$, and order the least whole number greater than that, meaning she should order $23 {\text{ft}}^{3}$ of cement.

If Valerie does not have a calculator, she can work out some squares of whole numbers to find out that

${22}^{2} = 484 < 500 < 529 = {23}^{2}$

As ${22}^{2} < 500 < {23}^{2}$, that means $22 < \sqrt{500} < 23$. Thus, without calculating the actual value of $\sqrt{500}$, she can still tell that $23$ is the least whole number which is greater than $\sqrt{500}$, and then order $23 {\text{ft}}^{3}$ of cement.