Answer:
+12.5%
Explanation:
This is rather simple. Subtract 72 from 81, then put the difference over 72. Then, multiply that by 100.
(81 - 72)/72 * 100
Subtract 72 from 81 to get 9
9/72 * 100
Multiply 9 by 100 to get 900
900/72
Simplify the above fraction by cancelling out 9.
100/8
Divide 100 by 8 to get 12.5%
The percent of change is +12.5%