If a triangle was rotated about the y-axis, as seen in the picture below, what 3-d shape would be created

Elena and her husband marc both drive to work. elena's car has a current mileage (total distance driven) of 15,000 and she drives 23,000 miles more each year. marc's car has a current mileage of 46,000 and he drives 9,000 miles more each year. will the mileages for the two cars ever be equal? explain.

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'