Let f be the height of the fir trees
Let p be the height of the pine trees
We know from the problem that
f + p = 21 and 4f = 24 + p
rearrange the 2nd equation to get p = 4f - 24 and substitute into the other equation
so...
f + 4f - 24 = 21
5f - 24 = 21
5f = 45
f = 9 - height of the fir tree
substitute back into the 1st equation
9 + p = 21
p = 12 - height of the pine tree
The base is the greatest surface area
<h3>
Answer: 5 cakes</h3>
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Explanation:
Let's start off converting the mixed number 12 & 1/4 to an improper fraction.

Do the same for the other mixed number 2 & 1/3.

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From here, we divide the two fractions. I converted them to improper fractions to make the division process easier.

The last step is to convert that result to a mixed number.

Note that 21/4 = 5.25 and 1/4 = 0.25 to help check the answer.
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Therefore, she can make 5 cakes. The fractional portion 1/4 is ignored since we're only considering whole cakes rather than partial ones.
24 in²
6x4-24
multiply the base times the height.