Given sec A=5/3 and that angle A is in Quadrant I find the exact value of cc’d A in simplest radical form using a rational denominator

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

Can someone answer this question for me

Melanie is buying a bathing suit that costs 39.99. she is given a discount at the cash register of $6.00 when she scratched 15% off on a game piece for a store promotion. what will the sale price of melanie’s bathing suit be?