Find the area of the rectangle, the hint gives us when you put the rectangle on its side can be multiplied it by 1/2 it will be the same as the length that we need for the area formula.

11700 mm²

Step-by-step explanation:

Vertical height between the centres of top and bottom circles

sqrt[(2×28)² - 28²]

= 28sqrt(3)

Width of the rectangle

= 4×28

= 112

Length of the rectangle

= 28sqrt(3) + 2(28)

= 56 + 28sqrt(3)

Area = 112 × (56 + 28sqrt(3))

= 11703.71133 mm²