Part A
<h3>Answer:
h^2 + 4h</h3>
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Explanation:
We multiply the length and height to get the area
area = (length)*(height)
area = (h+4)*(h)
area = h(h+4)
area = h^2 + 4h .... apply the distributive property
The units for the area are in square inches.
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Part B
<h3>Answer:
h^2 + 16h + 60</h3>
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Explanation:
If we add a 3 inch frame along the border, then we're adding two copies of 3 inches along the bottom side. The h+4 along the bottom updates to h+4+3+3 = h+10 along the bottom.
Similarly, along the vertical side we'd have the h go to h+3+3 = h+6
The old rectangle that was h by h+4 is now h+6 by h+10
Multiply these expressions to find the area
area = length*width
area = (h+6)(h+10)
area = x(h+10) ..... replace h+6 with x
area = xh + 10x .... distribute
area = h( x ) + 10( x )
area = h( h+6 ) + 10( h+6 ) .... plug in x = h+6
area = h^2+6h + 10h+60 .... distribute again twice more
area = h^2 + 16h + 60
You can also use the box method or the FOIL rule as alternative routes to find the area.
The units for the area are in square inches.
