This can be solved algebraically. Before we start, as context, to find a percentage you multiply by the percentage/100.
This tells us that 90 is
120% of 75. However, your question wants us to find the <em>increase</em>, therefore we don't need that 100.
Therefore, the increase is
20%.
$9802.90
17.4% = 0.174
so retail price = 8,350 + 8,350 * 0.174
= $9802.90
The living room has an area of 75 feet.
The drawing has an area of 47.25 inches.
75-47.25=29.75
DF = 2.68
EF = 4.477611940298507
(I think)