Answer:
If 9 of the sparrows is 45% of the birds in the backyard, 9/x = 45/100.
Cross multiply to get 9 * 100 = 45x; simplified is 900 = 45x or 20.
This means that there are 20 birds in the backyard. You can check this by dividing 9/20 which equals 45%
none??' you mean nine?
