Which equation has a constant of proportionality equal to 1

Three cylinders have a volume of 2836 cm^3. cylinder a has a height of 900 cm. cylinder b has a height of 225 cm. cylinder c has a height of 100 cm. find the radius of each cylinder. use 3.14 as an approximate for π

Which radical expression is a rational number? a. √ 360 b. √ 644 c. √ 225 d. √ 122

The gdp is $1,465.2 billion. the population is 249,793,675. find the per capita gdp.