Pls help me with this l did not get it

Suppose you have three polarizing filters, with the second at an angle of 42∘ to the first and the third at an angle of 90∘ to the first. by what perfect will the original intensity of unpolarized light be reduced to after passing through all three filters?

What is the measurement of how fast an object moves relative to a reference point?

Multiply or divide to make this english distance conversion. 174 inches = feet (14.5, 58, 2,088, 23)