Respuesta :

you take out the squares inside of the radicals. you can do this by factoring each number. 90 is a multiple of 3x3x2x5 and 40 is 2x2x2x5. now you take out pairs. so its (3√2x5)/(2√2x5). then you cancel out the √2x5 and you're left with 3/2. :)