Solve the proportion y/25=12/10

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

The perimeter of an equilateral triangle is 4 cm more than the perimeter of a square and the length of a side of the triangle is 8 cm more than the length of a side of the aware. find the length of a side of the equilateral triangle

Two farmers pay a total rent of $140 for a pasture. the first farmer placed $4 oxen in the pasture, and the second farmer placed $30 sheep in the pasture. the farmers split the rent based on the proportion of the pasture eaten by their own animals that month. how much should the first farmer pay, if 1 ox eats as much as 10 sheep in a month?