Learning Target: I can compute the surface area of a solid shape by adding areas.

The surface area of a solid figure is the sum of all of the areas of its faces. 

The net, or the "unfolded" solid, can help to determine the faces of a solid figure.

Example

Find the surface area of the rectangular prism shown.

Think--

• Visualize the net of the prism. 
• Sketch or imagine each face. 
• Then find each area and add them together.
   

Add the areas of all six faces.

24 + 24 + 18 + 18 + 12 + 12 = 108 

 

Let's Practice Together

Find the surface area of the solid figure.  Sketch a net or use a chart to help you.

1.

2.

Your Turn

3.

4.

5.

6.

 Check for Understanding
1.  Complete the table.

Answers

1.  208 m²
 

2.  8.64 dm²
 

3.  7 ft²
 

4.  36 cm²
 

5.  576 cm²
 

6.  73 ¹/₂ in²
 

Check for Understanding

1.  
3 cm → 9 cm² → 54 cm²
15 cm → 225 cm² → 1350 cm²