Find the unknown measure of the rectangle? 20ft, perimeter = 54 feet

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

Given a: b and b: c, find a: b: c. write the ratio in simplest form. a: b=6: 10 and b: c=21: 33

Oliver read for 450 minutes this month his goal was to read for 10% more minutes next month if all of her medicine go how many minutes will you read all during the next two months