Starters

Starter: Matching circumferencesPaul measured some circular objects but got them muddled up and measured one incorrectly.Work out the correct values and correct the mistake.

Diameter Circumference Diameter Circumference

3 cm 5 cm

25 cm 16 cm

4 m 6.5 cm

10 cm 5 mm

Choose from: 20.5cm 9.4cm 1.6cm 8cm50cm 13m 78cm 31cm

9.4cm

78cm

13m

31cm

8 cm x50cm

20.5cm

1.6cm

15.5 cm

Starter: What is a prism?

No – just 2 dimensional

No – 3D but not exactly the same cross-section

Yes – 3D and exactly the same cross-section

Starter: Matching the areasFor each of these 2 dimensional shapes, match it with the correct area. All measurements are in cm.

Choose from: 68 cm2 70 cm2 72 cm2 75 cm2 78.5 cm2 80 cm2

12

10

14

15

20

14

6 5

4

10

Example Questions

Practice: Surface area of a cylinder

Find the surface area of these cylinders:1) Radius 7 cm and Height 5 cm

2) Radius 10 cm and Height 15 cm

3) Diameter 4 m and Height 8 m

4) Radius 50 mm and Height 10 cm

5) Diameter 20 cm and Height 0.7 mChallenge

A cylinder has surface area of 942 cm2.

Its radius is 3cm. What is its height?

Answers:1) 527.52 cm2 2) 1570 cm2

3) 125.6 m2 4) 471 cm2

5) 5024 cm2 or 0.5024 m2

Challenge: 47 cm

Practice: Volume of a cylinder

Find the volume of these cylinders:1) Radius 10 cm and Height 15 cm

2) Diameter 6 m and Height 12 m

3) Radius 20 mm and Height 5 cm

4) A cylinder has volume of 7693 cm3. Its radius is 7cm. What is its height?

5) The volume of a cylinder is 1962.5 cm3. Its height is 100cm. What is its radius?

Answers:1) 4710 cm3 2) 339.12 m3 3) 62.8 cm3 4) 50 cm 5) 2.5 cm

Practice: Volume of a prismsFind the volume of these prisms:

6cm

8cm

20cm 2.5 cm

8cm

23cm

9cm

11cm

7cm 5.5cm

6cm

10cm

Answers: 480cm3 230cm3 693cm3 330cm3