I just started this chapter someone help me with these 2 questions

Answers: For the yellow one it’s 14
For the red one it’s 15

Long so the way to do this is to find the ratio. So you look at the filled shape for the yellow ones case it’s the smaller one and the sides have a ratio of 9:6 or 3:2, now since on the other similar shape the 9 lines up with 21 we can divide that by 3 getting us 7 and multiply that by 2 and get 14.

For the red one it’s the same process, 8:6=4:3 so we and we divide 20 by 4 and get 5, then multiply that be 3 and get 15.

Please mark brainliest if this helps.