# Surface Area Examples

### Example 1

 This cube has six congruent faces, each with a length and width of 3 cm.Area of one face = 3 x 3 cm = 9 cm2Surface area = 6 sides x 9 cm2 = 54 cm2

### Example 2

This trapezoidal prism has six sides, two congruent trapezoids and four rectangles.

 Trap 1 ½(10 + 4) x 2 14 cm2 Trap 2 ½(10 + 4) x 2 14 cm2 Rect 1 3.6 x 7.0 25.2 cm2 Rect 2 4.0 x 7.0 28 cm2 Rect 3 3.6 x 7.0 25.2 cm2 Rect 4 10.0 x 7.0 70 cm2 Total 176.4 cm2

### Example 3

This cylinder has two circles (each with a radius of 2 cm) and one rectangle (with a length of 5.8 cm and a width the circumference of the circles).

 Circle 1 π x 22   = 4π 12.56 cm2 Circle 2 π x 22   = 4π 12.56 cm2 Rect 1 5.8 x 4π = 23.2π 72.85 cm2 Total 97.97 cm2

### Example 4

 This pyramid is made up of four equilateral triangles. Here we just need to find the area of one triangle and multiply it by four sides:Area of 1 triangle = ½bh = ½(8 x 6.9) = 27.6 cm2Now, multiply that by four sides, and we're done.110.4 cm2

### Example 5

 The diameter of this sphere is 11.9 cm, so the radius is half of that, 5.95 cm.

### Example 6

 The area of the circular base is equal to: