Hellppppp

= sqrt ( 64/100 + 225/100) = sqrt ( 289/100) = 17/10

$\displaystyle \sqrt{\frac{16}{25}+\frac{9}{4}}\ =\ \sqrt{\frac{16\cdot4}{25\cdot4}+\frac{9\cdot25}{4\cdot25}}\ =\ \sqrt{\frac{64}{100}+\frac{225}{100}}\ =\ \sqrt{\frac{289}{100}}\ =\ \frac{\sqrt{289}}{\sqrt{100}}\ =\ \frac{17}{10}$