Question

So confused... help again?

Answer 1

Andre made a wax model of a rolling pin of diameter 4 cm. The rolling pin was shaped like a right circular cylinder with a right circular cone at each end as shown below.

What was the total surface area of the rolling pin? Using complete sentences, describe the steps you used to calculate the surface area.

Answer 2

(wait, I'll give a picture then my answer)

Answer 3

My answer:

SA = 2(pi)r*h
SA = 2(3.14)(2)(13)
SA = 163.28

SA = (pi)r*l
SA = (3.14)(2)(7)
SA = 43.96

SA = 2(pi)r*h + 2(pi)r*l = 2(pi)r(h+l)
SA = 2(3.14)(2)(13) + 2(3.14)(2)(13+7)
SA = 163.28 + 251.2 =

Total surface area = 414.48

Answer 4

ok one sec

Answer 5

@Hoa or @Directrix ?

Answer 6

okay @jim_thompson5910 :)

Answer 7

This is the lateral surface area of the cylinder in the middle

SA = 2(pi)r*h
SA = 2(3.14)(2)(13)
SA = 163.28

and this is correct

Answer 8

The lateral surface area of each cone on the endpoint is

SA = pi*r*s ... Note: s is the slant height of the cone

SA = 3.14*2*7

SA = 43.96

Answer 9

There are 2 such cones with the same lateral surface area, so the combined lateral surface area of the cones is 43.96+43.96 = 87.92

Answer 10

Total Surface Area = (Lateral Surface Area of Cylinder) + (Lateral Surface Area of Cones)

Total Surface Area = (163.28) + (87.92)

Total Surface Area = 251.2

Answer 11

WOW! I was so off!! Lol. Thank you so much for explaining :)

Answer 12

you're welcome

Answer 13

Have a wonderful day! :)

Answer 14

you too