What precent is 3/5 is 9/10 ?

Can someone me do math because i am having a breakdown rn because i don’t get it

Geometry - finding area of regular polygons and sectors (check my math, i can’t find the error)

Paco orders an ice cream for $1, but realizes his wallet is at home and he only has 3/20 of $1 with him. if his mom pays the remaining 7/20 of the dollar, how much will she pay? $0.05 $0.15 $0.85 $0.95