To use HL specifically they would need to have the same hypotenuse as well as a right angle.
I am confused what is your question then i will tell you the answer.
(a) One possibility is 8.45
Rounded to the nearest integer = 8
Rounded to the nearest tenth = 8.5
And rounding this to the nearest integer = 9
(b) The possible numbers are 8.45 to 8.49, inclusively
The answer is 13/20. So 3/5 is equal to 6/10 so you're looking for the fraction that's half of 7/10 and 6/10 which is 6.5/10 but you can't use decimals in a fraction so you multiply both sides by 10 which would equal 65/100 and simply, and that would be 13/20.