Given segment de is parallel to segment bc, what postulate or theorem can be used to prove the triangles are similar

Find the average rate of change for f(x) = x2 − 3x − 10 from x = −5 to x = 10.

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?

Due to a packaging error, 4 cans labeled diet soda were accidentally filled with regular soda and placed in a 12 pack carton of diet soda. two cans were randomly selected from this 12 pack. what is the probability that both cans were regular soda?