Chapter 6 - Radical Functions and Rational Exponents - 6-7 Inverse Relations and Functions - Practice and Problem-Solving Exercises - Page 412: 87

$3$

To find the root of this radical, we will rewrite the radicand as a base raised to the 5th power because we want to take the 5th root of this number. We rewrite $243$ as $3^5$: $\sqrt[5] {243}$ = $\sqrt[5] {3^5}$ To get rid of the radical, we take the 5th root of $243$: $\sqrt[5] {243}$ = $3$ We only want to take the real roots, so $3$ is a valid answer because it is a real number.