SA & Volume Applications

1. How many feet of form board are needed to enclose a 4 by 6 foot concrete pad?

6 ft

4 ft

perimeter = 20 ft

SA & Volume Applications

2. The bore of a cylinder is its diameter, the stroke is its height, and the displacement is its volume. What is the displacement of a cylinder with a bore of 56.5 mm and a stroke of 48.5 mm? Give the answer in cubic centimeters.

volume = Bh V = (base area) (dist b/w bases) V = (r2)(h)V = (3.14)(2.825)(2.825)(4.85)V = 121.5cm3

48.5 mm4.85 cm

56.5 mm

5.65 cm

SA & Volume Applications

3. If asphalt pavement costs $0.78 per square foot, determine the cost of the circular road in the figure.

Aouter circle = r2 = 3.14(50)(50) = 7850 ft2

36’

50’

Ainner circle = r2 = 3.14(36)(36) = 4069 ft2

Aouter circle – Ainner circle = 7850 – 4069 = 3780.56 ft2

Cost = (3780.56)(0.78) = $2948.84

SA & Volume Applications

4. A 6 inch diameter pipe 50 feet high is filled to the top with water. What is the weight at its base? (Note that one cubic foot of water weighs 62.4 pounds.) Round to the nearest pound.

6”

50’

d = 0.5 ft

volume = Bh V = (base area) (dist b/w bases) V = (r2)(h)V = (3.14)(0.25)(0.25)(50) = (0.196)(50) = 9.81 ft3

Weight = (9.81)(62.4) = 612 lbs

SA & Volume Applications

3. A customer wants to surround a two-wall shower with synthetic marble to a height of 72”. If the two walls measure 36” and 78” and marble costs $35 per square foot, what is the total cost of the marble?

50’

Aback = lw = (6)(6.5) = 39 ft2

72”

78”

36”

6 ft

6.5 ft

3 ft

Aside = lw = (6)(3) = 18 ft2

Atotal = 39 + 18 = 57 ft2

cost = (57)(35) = $1995