Question

The following figure shows a square cardboard ABCD of side 28 cm. Four identical circles of the largest possible sizes are cut from this card as shown below.

Find the area of the remaining card-board.

Answer 1

Area of the square is given by

A = 28²
   = 784 cm² 

Since there are four identical circles inside the square.
Hence the radius of each circle is one-fourth of the side of the square.

Area of one circle = π x 7²  
                             = 154 cm²

Area of four circle = 4 x 154cm²  
                             = 616 cm² 

Area remaining = 784 - 616
                          = 168 cm² 

The area remaining in the cardboard is = 168 cm².