Well if its fora circle it would be r ( radios, Half of the Diameter) divided by 9
Estimation would give you an answer close to the actual answer so you can see if your answer is reasonable depending on how close the estimate is
Percent change=change/original times 100
chane=28-23=5
oriiginal=28
percent change=5/28 times 100
0.178 times 100
17.8
about 18% change
1.20 + 0.34 = 1.54
That is the answer.
The answer is: 2a^4 - 3a^2 b - 5b^2
