CSLB Concrete C8 License Practice Test #1 Questions and Correct Answers

CSLB Concrete C8 License Practice Test #1 Questions and Correct Answers What is the volume of a cylinder if the diameter equals 3 feet and the length equals to 12 feet? - Correct Answer 84.78 cubic feet Explanation: There are two ways to solve the problem. However, regardless of which method is used, you need to first determine the area of the circle then multiply it by the length.Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 and radius (r) = 1.5 feet (half of the diameter length)Area = 3.14 x 1.5 x 1.5Area = 7.065 sq. ft.Multiply area by the length to find the volume.7.065 x 12 = 84.78Shortcut MethodArea of the circle is 78.5% of the square. Treat the circle as a square and solve for the area.Find the area of the square instead of the circle.3' x 3' = 9 sq. ft.Since circle is 78.5% of the square, multiply area of the square by 78.5% (or .785 if there is no percentage sign on the calculator).9 sq. ft. x .785 = 7.065 square feetMultiply area by the length to find the volume.7.065 x 12 = 84.78 cubic feet Where are spiral rebar ties used? - Correct Answer In round columns Control joints in sidewalks should be spaced at what intervals? - Correct Answer Equal to the width of the slab Explanation: Generally the control joints in sidewalks should be spaced equal to the width of the slab, but not more than 6 feet apart. One cubic foot of cement weighs approximately: - Correct Answer 95 lbs How many cubic yard of concrete is required for a 4" slab with the diameter of 15 feet? - Correct Answer 2 ½ cubic yards Explanation: Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 and radius (r) = 7.5 feet (half of the diameter length)Area = 3.14 x 7.5 x 7.5Area = 176.625 sq. ft.Multiply area by the depth of the slab (in feet) to find the volume in cubic feet.176.625 x .333 = 58.82 cubic feetConvert cubic feet into cubic yards.58.82 ÷ 27 = 2.18 cubic yardsSince 2.18 is not a given option, round up the number to 2.5 cubic yardsShortcut MethodThis problem can be solved using a much simpler method. First is to find the area of the square, then convert it into the area of the circle by multiplying it by 78.5%.Area of the square = 15' x 15' = 225 square f