Answer:
The side lengths are:
15, 30, and 30
Explanation:
Let x determine the length of the smallest side length then
the other one is said to be 15 in larger so it's x + 15
finally the third size is said to be twice as the smallest one so it's 2x
The perimeter is the sum of all three sides added up
x + 2x + x + 15 = 75 add like terms
4x + 15 = 75 subtract 15 from both sides
4x = 60 divide both sides by 4
x = 15