I need help with the first one only just so I can understand the rest of them

Volume of cylinder with a radius of 8cm and height of 25 cm

Which expression gives the exact value of x?

Asunflower was 20 1/2 inches tall. over the next 6 months, it grew to a height of 37 inches tall. what was the average yearly growth rate of the height of the sunflower? ? plz write a proportion to solve i will give you 100 points