7. Do you prefer to find the surface area of a cylinder by using the sum of the area of each face or by using a formula? Give at least two reasons for your choice.

A: I prefer to use a formula because it is quicker and I'm less likely to miss a part of the calculation.

9. Kaitlyn and Hakim each bought a tube of candy. Both containers cost the same amount . Which container required more plastic to make?

Container A:

diameter- 7 cm

height- 122 cm

radius- 3.5 cm

SA=2.π.r.r+2.π.r.h

SA=2(3.14)(3.5)(3.5)+2(3.14)(3.5)(122)

SA=76.93+2681.56

SA=2758.49 cm²

Container B:

diameter- 11 cm

height- 85 cm

radius- 5.5 cm

SA=2.π.r.r+2.π.r.h

SA=2(3.14)(5.5)(5.5)+2(3.14)(5.5)(85)

SA=189.97+2935.90

SA=3125.87 cm²

Container B required more plastic to make.

10. Paper towel is rolled around a cardboard tube. Calculate the outside surface area of the tube.

radius-2 cm

height- 27.5 cm

outside SA=2.π.r.h

outside SA=2(3.14)(2)(27.5)

outside SA=345.4 cm²

Cylinder Volume and Volume Problems

Solution:

JUMBO

r= d/2 r=20/2 r=10 cm V= πrrh V= [(3.14)(10)(10)](40) V= (314cm²)(40cm) V= 12560cm³

POPCORN LOVER'S

r=d/2 r=30/2 r=15 cm V= πrrh V= [(3.14)(15)(15)](20) V= (706.5cm²)(20cm) V= 14130cm³

Martha should buy Popcorn's Lover if she wants more popcorn for her money.

Solution:

outside

r=d/2

r=1/2

r=0.5m

V=πrrh

V=[(3.14)(0.5)(o.5)](10)

V=(o.785m²)(10m)

V=7.85m³

inside

r=d/2

r=0.8/2

r=0.4m

V=πrrh

V=[(3.14)(0.4)(0.4)](10)

V=(o.5024m²)(10m)

V=5.024m³

7.85m³-5.024m³=2.862m³ or 2.9m³

The volume of the concrete required to make the culvert is 2.9m³.

Great job Ysabelle. Your post was really well explained. I liked that you used different colors for the answers and that you wrote down the questions. Next time add a link to make it better. Other than that, great job.

ReplyDeleteGood job! Very clear and self explanatory. Next time add a link.

ReplyDeleteGreat post Ysabelle. I liked that your post is well explained and also you separated the answers and questions using color. Nest time you should add a link.

ReplyDeleteGood work Ysabelle! The scribe is very neat, organized and easy to understand. I suggest you add a link next time, it'll make your scribe complete. Anyway keep up the good work.

ReplyDelete