Help me please I have little of time

The multiplicative property of equality states that for real numbers a, b, c, and d, if a = b and c = d, then ac = bd. true false

Find the magnitude, correct to two decimal places, made by each of the following with positive direction of the x axis a) y= x the answer is 45° but i don’t know how

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2