Question 2. :
8^2 = 64 and 9^2 = 81, therefore the square root of 65 falls between these two values, 8 and 9, 64<65<81
Question 3. :
13^2 = 169 and 14^2 = 196, the correct answer is square root of 175, because 169<175<196
Hope this helps, you only need to know the squared values and square roots.
