Per a mesurar l'alçada d'un fanal, durant el dia, la Laura en farà servir l'ombra. Pot mesurar l'ombra del fanal, que fa 9 metres, així com la seva pròpia ombra, que fa 2,40m. Si ella sap que medeix 1,60m, quina mida té el fanal?

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.