Surface Area

REVIEW Write the definition (associated with math) of the following terms. Please use your own words and provide an example.

Area Net

Surface Area

ACTIVITY

Surface Area of a Rectangular Prism 1. You are the manager at the Smarties factory. Times are tough and you need to find a new paint company to cover your boxes with paint. First you need to find the surface area of your boxes.

2. Obtain a Smarties box from Mrs. Attwater. Do not open or eat them until directed to do so.

3. Carefully open the box and dump out the Smarties. You may now eat them while working on the assignment.

4. Follow the instructions on taking the box apart.

5. Place the box on the 1 cm grid paper below and trace around it. Be neat and careful. 6. What do you notice about the net of a rectangular prism?

7. Calculate the surface area of the box.

8. Is unfolding a rectangular prism, laying it flat and measuring it an efficient way to calculate the surface area? Why? Why not?

9. Create a formula that would help you calculate the surface area of a rectangular prism.

Surface Area of a Cylinder 1. Obtain a copy of the net of a cylinder from Mrs. Attwater.

2. Carefully cut it out.

3. Form it into a cylinder several times so you can understand how it comes together. This is very important!

4. What do you notice about the net of a cylinder?

5. Calculate the surface area of the cylinder.

10.Is unfolding a cylinder, laying it flat and measuring it an efficient way to calculate the surface area? Why? Why not?

6. Create a formula that would help you calculate the surface area of a cylinder (HINT try step 3 again).

DISCUSSION 1. Based on the activity, what can you conclude about finding surface area of 3D shapes?

2. Find the surface area formulas for the following shapes. Shape Formula Shape Formula

PRACTICE 1. Calculate the surface area of the following shapes.

10 cm 2. Jemma has built this doghouse. The roof is a triangular prism with an isosceles triangle base. There is an overhang of 0.1 m. There is an opening for the doorway.

a. Determine the surface area of the doghouse.

b. The doghouse will be covered with 2 coats of stain. One litre of stain covers 6m2. How many litres are needed?

c. One litre costs $16. How much will this cost Jemma?

3. Each layer of a three tiered cake is a cylinder with a height of 7.5 cm. The bottom tier has a diameter of 25 cm. The middle tier has a diameter of 22.5 cm and the top tier has a diameter of 20 cm. The surface of the cake needs to be frosted.

a. Sketch the cake

b. What area of the cake needs to be frosted?

c. One cup of frosting covers 100 cm2 of cake surface. How many cups are needed to frost the whole cake? Marking Scheme Please attach this to your final assignment

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Challenge Without using the internet, find the formula for the surface area of a cone. The net is below. Hint: compare the sector to the whole circle and use this diagram below.