The amount of paper that Lemon needs for the actual poster will be 8 square feet.
<h3>What is a rectangle?</h3>
It is a polygon with four sides. The total interior angle is 360 degrees. A rectangle's opposite sides are parallel and equal, and each angle is 90 degrees. Its diagonals are all the same length and intersect in the center.
The dimension of the poster is 10 cm by 20 cm.
And the scale factor will be 5 cm is equal to 1 ft.
Then the dimension of the poster will be 2 ft by 4 ft.
Then the amount of the paper that Lemon needs for the actual poster will be
Area = 2 × 4
Area = 8 ft²
More about the rectangle link is given below.
brainly.com/question/10046743
#SPJ1