Question

Donna wants to cut out circular discs of radius 7cm from a cardboard measuring 50cm by 70cm. What is the maximum number of circular discs that can be cut out from the cardboard?

Answer 1

Area of disc (circle):
A = pi*r^2
A = 3.14 * 7^2
A = 153.86 cm^2

Area of cardboard (rectangle):
A = L * W
A = 70 * 50
A = 3500 cm^2

Divide area of rectangle by area of circle:
3500 / 153.86
= 22.75
Take only the whole number: 22 discs

Hope this helps :3

Answer 2

However, all the scrap pieces cannot be used to form whole circles, so, assuming a rectangular packing of the circles, only 5 discs can be fit along the length of the cardboard. The diameter of 14 cm means that only 3 can fit across. That means that only 15 discs can be cut.

A hexagonal packing will allow for more, and I'll leave you to determine how that affects the total.

Answer 3

i think only 15 numbers of discs will make from this 50 x 70cm card board