Kareem cuts 12 identical circles of pastry form a 30cm by 40cm sheet. Find the area of pastry {which remains}

Work Shown:

The area of the rectangle is 40*30 = 1200 square cm

Note how we have 4 circles along the horizontal dimension which is 40 cm, so each diameter is 40/4 = 10 cm, and the radius is 10/2 = 5 cm

Each circle has an area of pi*r^2 = pi*5^2 = 25pi

There are 4*3 = 12 circles, so the circle areas combine to 12*25pi = 300pi

Using a calculator, we find that 1200 - 300pi = 257.522203923062 approximately. Round this however you need to.

a. is correct