Chapter 10 - Radical Expressions and Equations - 10-4 Solving Radical Equations - Practice and Problem-Solving Exercises - Page 636: 17

Swing should be $5.156ft$ long

Therefore: $t = 2.5 =2\sqrt {\frac{l}{3.3}} $ $\implies \frac{5}{2} = 2\sqrt {\frac{l}{3.3}} $ Squaring both sides, $ \implies \frac{25}{4} = 4{\frac{l}{3.3}} $ $ \implies \frac{25}{4 \times 4} * 3.3 = l $ $ l \approx 5.156 $