It is 750.
750.0
750% of 900 is 6750. No rounding necessary.
Anything five and over is rounded up, anything four and under is rounded down, 3 is less than four, therefore the answer is 750.
It is already rounded to the nearest ten.
800
740
800
750
750
750
The smallest number that would round up to the nearest 100 to make 800 is 750.