Question

Discs of radius 4cm are cut from a rectangular sheet of length 84cm and width 24cm. How many complete discs can be cut out?

Answer 1

So a 4*4 cm square.

Since the width is 24cm then we can fit 6 disks and the height is 84cm so we can fit 21

6*21=126 disks

Answer 2

Area of the rectangular sheet = 2016 sq. cm
Area of one disk = 50.24 sq. cm.
So now you just have to divide.

Answer 3

40??

Answer 4

but my text gives the answer 30

Answer 5

Yes, its 40.

Answer 6

Textbooks can be occasionally wrong.....

Answer 7

And Zed, you must have misunderstood, a disk is a circle, not a square.

Answer 8

Sorry I thought the diameter was 4. So we can have 3 disk in the width (24/8) and 10 disk in the height (84/8).

So the total number is 3*10=30

Answer 9

Because the distance from the center of the circle is 4cm. It must fit in a 8*8cm square.

Answer 10

@pratu043, the area of 40 disks can be cut out of the sheet, however they will not be the shape of a disk.

Answer 11

why did you divide the diameter by the length and height of the rectangle????

Answer 12

and were did the 10 come from???

Answer 13

okay the disks will fit in a 8x8 square. do you understand this?

Answer 14

where did you get 8x8 from?

Answer 15

okay because the radius of the circle is 4, its diameter must be 8. and the diameter cannot change so it is 8 for the whole circle.

Now because the circle is not longer than 8 cm it must fit into a 8x8 square. do you follow?

Answer 16

yes

Answer 17

okay so now what i'm trying to find is how many of these squares fit into the rectangular sheet.

Answer 18

for the width i can fit 3.
because 24/8=3

for the height i can fit 10.
because 84/8=10.5 but 10.5 won't make a disk so we must we 10.

So the the amount of disks=number for width*number for height
=3*10
= 30

Answer 19

impressive