Surface area of prisms

Question 1

Find the total surface area of the rectangular prism in the diagram on page 1, where dimensions are 3 cm x 5 cm x 4 cm.

Solution

To solve this we need to find the area of the six individual rectangles which make up the rectangular prism. There are three different rectangles and two of each type.

TSA of a rectangular prism = 2L × W + 2L × H + 2W × H

Taking out a common factor of 2:

TSA of a rectangular prism	= 2 (L × W + L × H + W × H )
	= 2 (5 × 3 + 5 × 4 + 3 × 4 )
	= 2 (15 + 20 + 12 )
	= 2 × 47
	= 94 cm².

Question 2

Find the total surface area of a rectangular prism, where dimensions are 6 cm x 5 cm x 2 cm.
 cm²

Surface area of prisms

Triangular prisms