Question

Given a circle A whose diameter is 2 ft.and a rectangular piece of tin B,10ft by 4 ft.Find, correct to the nearest square foot, the tin that will be left after the greatest possible number of circles of the size of A have been cut from B.

a. zero
b. 1 sq.ft
c. 2 sq.ft
d. 9 sq.ft
e. 20 sq.ft

please answer and explain

Answer 1

I will assume that you know how to find the area of a circle. In this case, that will be π ft^2

I must also assume you haven't studied packing density of circles, so we'll say the centers of the circles lie on a square grid. That said, since each circle has diameter 2, the piece of tin is 5x2 circles in size.

So, the leftover area is 10*4-10π = 40-31.4 = 8.6 or 9 ft^2