1. 3.1 Surface Area of Prisms
October

2. Lesson Outline What is surface area? What is a prism?
How do you find surface area of common shapes? (Oct 25th)
How do you find surface area of a prism?
Drawing the nets of a 3D shape

3. What is Surface Area?
The surface area is the total area that covers a three dimensional shape
E.g. the surface area of a box can be found by unfolding it and flattening it out

4. What is a Prism
A prism is a 3D object that has two parallel congruent polygons, with sides that are parallelograms
In other words, a 3D object with 2 shapes on opposite sides, and four sided shapes in between them

5. Which of these are prisms?

6. What is a Prism ? Right Right Rectangular Triangular Prism Prism
Prisms are named for the shapes on their sides ?
Right
Rectangular
Prism
Right
Triangular
Prism

7. What is a Prism
Prisms are also named for whether the shapes on opposite ends are directly on top of each other.

8. What is a Prism
Prisms are also named for whether the shapes on opposite ends are directly on top of each other.

10. Surface area of a flat shape
How do I find the surface area of the rectangle below?
What are two pieces of information I need, and what do I do with them?

11. Surface area of a flat shape
Width
Length
Length x Width = Surface area of Rectangle

12. Surface area of a flat shape
How do I find the surface area of the triangle below?
What are two pieces of information I need, and what do I do with them?

13. Surface area of a flat shape
Base x Height 2

14. Surface area of a flat shape
Base x Height 2
Why divide by 2?

15. Surface area of a flat shape
Base x Height 2
Notice that it is height not side

16. Surface Area of a Circle

17. Surface Area of a Circle
Pi = …
r = radius

18. Surface Area of a Circle
12 cm
A = πr2
A = π(6)2
A = 36π
A = 113 cm2

19. Math Connect Activity

20. Surface Area of a Parallelogram
Why?
Base x Height
(NOT SIDE)

21. Surface Area of a 3D shape
If we were to unravel a 3D object, it would be made up of multiple 2D shapes.

22. Activity (5 min)
Using a ruler, find the surface area of two rectangular prisms
You may use the ones provided or find your own

23. Surface Area of 3D Shape
The formula of SA of rectangular prism
2 WH + 2 LW + 2 LH
NOTE: It doesn’t matter which you make the length, height and width

24. Surface Area of 3D Shape
2 WH + 2 LW + 2 LH W = 22 cm H = 7.5 cm L = 5.5 cm = 2(22 cm)(7.5 cm) + 2(5.5 cm)(22 cm) + 2(5.5 cm)(7.5 cm) = 330 cm cm cm2 = cm2

25. Drawing a Net
If I unfolded this Toblerone package, what would it look like?
What shapes would I have?

26. Drawing a Net
What is a net? – a two dimensional pattern that can be folded to form a three dimensional shape

29. Surface Area of 3D Shape

30. Toblerone Activity (5 min)
15 cm
3.5 cm
2.4 cm
Label the dimensions of the Toblerone package onto the net, then find the surface area

31. Homework