7. suppose a student stacks 1000 congruent circles one on top of the other, and the teacher
1000 similar circles, with each circle a little smaller than the one below it.
a. what is the name of the solid formed by the stack of congruent circles?
b. relate the dimensions of one of the congruent circles to the dimensions of this solic
c. what is the name of the solid formed by the stack of similar circles?
d. relate the height of the stack of similar circles to a dimension of this solid.

See below.

Step-by-step explanation:

a. That would be a cylinder.

b.The height of the cylinder will be n * thickness of one circle where  n is the number of circles.  The volume of the cylinder is π r^2 h where h is the height of the stack.

c.  That would be a cone

d. The height of the cone will be n * thickness of one circle where n is the number of similar circles.

Volume of the cone = 1/3 * π r^2  h    where h is the height of the stack of circles.

the total estimated nappy use.=10,500,000

step-by-step explanation:

given that on an average the average baby uses 3528 napkins.

in a particular year 2014, the number of births were 299697 in new south wales.

rounding off the number of births to the nearest hundred thousand we have

no of birtsh = 300000

also rounding off the average usage to nearst thousand we get

average use of a baby = 3500

hence total number of nappy estimated to be used = 3500x300000

= 10,500,000

answer is 10,500,000 nappies