Warm up

Notes

Preliminary Activity

Activity

For Fun

Surface area of a cylinder

BackBack

Number_1.ppt

Significant Figures

BackBack

Surface Area of a Cylinder

A closed cylinder is made from two circular ends and a curved surface. This curved surface can be opened out into a rectangle.

The are of each end of the cylinder is calculated using the area of a circle formula

A = πr2

The area of the curved surface is calculated using the area of a rectangle formula

A = 2πrhThe surface area of a closed cylinder is

SA = 2πr2 + 2πrh

BackBack

Example

A closed can of baked beans has a base diameter of 7.4 cm and a height of 11 cm.a) What is the area of the label wrapped around the can if there is a 2 cm overlap? Answer to the nearest square centimetre.

b) What area of metal makes up the can? Answer to the nearest square centimetre.

Area of label = (2πr + 2)h = (2 x π x 3.7 +

2) x 11 = 277.7256 . . . ≈ 278 cm2

Total surface area is SA = 2πr2 + 2πrh = 2 x π x 3.72 + 2

x π x 3.7 x 11 = 341.7424 . . . ≈ 342 cm2

BackBack

Do Exercise 2.06page 61Questions 1 - 6

BackBack