Approximate rational numbers to the nearest 10th – We use the Pythagorean Theorem to find the missing diagonal in a square and rectangle. Then we found the decimal approximations of Square roots that are not rational. Next we reviewed that a rational number is a number that can be written as the ratio of two integers. An irrational number cannot be written as the ratio of two integers. So the square root of any whole number that’s not a perfect square is irrational and the cube root of any integer that’s not a perfect cube is irrational.