HELP PLEASE IM SO CONFUSED

Theater Club Stage Crew
The school's theater club is building sets that will make ordinary students look like giants. The actors need a door, a table, and a stool that will make them look almost twice as tall!

DOOR: actual height is 80 inches and Height on Set is 44 inches
TABLE: actual height is 28 inches
STOOL: actual height is 18 inches

The heights of the objects in the set are proportional to the actual heights of objects. What is the CONSTANT OF PROPORTIONALITY? Write as a whole number, decimal or fraction.

Alength on a map is 7.5 inches. thescale is 1 inch: 5 miles. what is theactual distance? a 1.5 miles c 12.5 milesb 2.5 miles d 37.5 miles

Michelle and julie work at a catering company. they need to bake 264 cookies for a birthday party that starts in a little over an hour and a half. each tube of cookie dough claims to make 36 cookies, but michelle eats about 1/5 of every tube and julie makes cookies that are 1.5 times as large as the recommended cookie size. it takes about 8 minutes to bake a container of cookies, but since julie's cookies are larger, they take 12 minutes to bake. a. how many tubes should each girl plan to bake? how long does each girl use the oven? b. explain your solution process what did you make? c. what assumptions did you make?

I’m still confused on how to work the percentages