75% of the normal price of headphones is 45$. What's the normal price?

60$ is the normal price.

Why:

Because if 45$ is 75%, then 30$ is 50%, 15 is 25%, and 0 is 0%. 50% + 50% = 100%. (That's how I did this one, anyway. This works on any 25%, 50%, or 75% problem.)

c. prove the lengths are the same.

step-by-step explanation:

you need to prove the segments are congruent. congruent segments have the same length. find the lengths of the segments using the distance formula, and compare them.

answer: c. prove the lengths are the same.

d? maybe

step-by-step explanation: