You must make a tape diagram going by 10 percents. 10, 20, 30... Then, put 180 over the 90 percent. Then, do 180 divide by 10 to find out 10 percent. That is 18. Then do 18 times 9 which is 162.
Also, you could make 90 a decimal. 0.90. 0.90 times 180 is 162.
