1. 1.3 Surface Areas of Objects Made from Right Rectangular Prisms

2. Determining the SA of a Composite Object Made From Cubes
Each cube has edge length of 2cm. Determine the surface area.

3. Method 1
Draw all 6 views and count all the squares.
Front
Left Side
Top 4 3 2
Bottom
Right Side 3
Back 2 4
Total: 18 Squares

4. The area of each square is:
A= l x w
A= 2cm x 2cm = 4 cm2
We have 18 of these squares, so:
Total Area = 18 x 4 cm2 = 72 cm2

5. Method 2
Our composite object is made up of 4 squares. Each cube has 6 square faces. So the total number of squares is: 4 x 6 = 18

6. The cubes overlap at 3 places, so there are 3x2, or 6 squares that are not included in the surface area.
So the surface area in squares is: 24 – 6 = 18
Each square has area 2cm x 2cm = 4cm2
So the surface area is 18 x 4cm2 = 72cm2

7. Determining the Surface Area of a Composite Object Made from Right Rectangular Prisms

8. 2 1 3 1 2 3 50 m 30 m 30 m 20 m 20 m 30 m 20 m 6 Squares, each have
side length 10m

9. My favourite method: Figure out the Surface area of all the objects.
Figure out the surface area where the objects overlap.
Subtract that area from the total.

10. Assignment Time