To start, find out 10 per cent of 150. To find a percent, divide by 100 and multiply by the percent. 150 divided by 100 is 1.5, 1.5 multiplied by 10 is 15. Finally, add the 10% on to the original, so 150 + 15 = 165cm. Alternatively, to find 10%, divide by 10, and continue to add to the original.