Vocabulary

Surface area – the sum of the areas of all of the surfaces of a three-dimensional figure.

Concepts

Identifying the calculation for the surface area of a prism

Rules

1. Determine whether the prism is rectangular or triangular.
2. If it is rectangular, then all six of the faces are rectangles.
3. If it is triangular, then two faces will be triangles and three faces will be rectangles.
4. Select the choice that represents the sum of the areas of the faces.

Example

From the choices below, select the correct calculation for finding the surface area of this prism.

Solution

The surface area is found by finding the area of each surface and adding them all together.

The top and the bottom areas are each 5 × 7.

The left and the right areas are each 2 × 7.

The front and the back areas are each 2 × 5.

S.A. = 2 × (2 × 5) + 2 × (2 × 7) + 2 × (5 × 7)

Pre-requisite Skills

Measurement - Area (4.13.8)

Area of a parallelogram (6.11.2)

Area of a triangle (6.11.3)

Surface Area of Rectengular Prisms (6.11.5)