Check the picture below.
you can pretty much count those lengths off the grid.
recall that A = 1/2 bh.
Answer:

Step-by-step explanation:
Answer:
There are multiple possibilities. One is there are 12 boys, and 16 girls. 12+16= 28 which is between 20 and 30. That would be 12:16, which can be simplified to 3:4. There is also 9 boys, and 12 girls. that would be 9:12, which can be simplified to 3:4. Also, 9 + 12 = 21, which is between 20 and 30.
Answer:
20%
Step-by-step explanation:
With those changes, the fraction is multiplied by ...

That is, the value of the fraction is decreased by 20%.