1. -4 and 3/10 and 4.51010910921... are all rational numbers.
2. Yes 81 is a perfect square because its square root is 9 which is a real number.
3. 5
4. Well the closest perfect square to 52 is 49 and 64. 52 is closer to 49 and the square root of 49 is 7 so the estimated value of the square root of 52 is about 7.
False- every square root is not rational because some aren't perfect squares, meaning the result is a decimal that keeps going forever.
5. (x+6, y-5)