### Home > CCG > Chapter Ch7 > Lesson 7.2.3 > Problem7-80

7-80.

It is often useful to estimate the value of a square root to determine if your answer is reasonable.

1. What would be a reasonable estimate of $\sqrt { 68 }$? Explain your thinking. After you have made an estimate, check your estimation with a calculator.

$\sqrt{68}\cong8.2$ because $\sqrt{64}=8$, so $\sqrt{68}$ must be a little higher.

2. Repeat this process to estimate the values below.

(1) $\sqrt { 5 }$

(2) $\sqrt { 85 }$

(3) $\sqrt { 50 }$

(4) $\sqrt { 22 }$

Since square root of $81$ is $9$, then square root of $85$ is a little more $\approx9.2$.