**Contents** • Section 1—Introduction to Plumbing • Section 2—Plumbing Systems • Section 3—Plumbing System Design and Installation • Section 4—Plumbing Services • Section 5—Career Development and Plumbing History

**Section 1** Introduction to Plumbing

**Chapter 4** Mathematics for Plumbers

**Objectives** • Read a rule accurately to nearest 1/16. • Add and subtract fractions and whole numbers. • Compute pipe offsets using the Pythagorean theorem and trigonometric functions. • Apply the formulas for finding area and volume. • Explain and apply SI metric measure in finding length, area, volume, and temperature. • Convert customary measure to metric measure.

**Measurement** (Goodheart-Willcox Publisher)

**Measurement** Reading Fractions of an Inch • Read from nearest 1/4 divisions to get precise reading. (Goodheart-Willcox Publisher)

**Measurement** Adding Lengths (Goodheart-Willcox Publisher)

**Measurement** Subtracting Lengths (Goodheart-Willcox Publisher)

**Measurement** Subtracting Unequal Denominators (Goodheart-Willcox Publisher)

**Measurement** Borrowing from the Whole Number (Goodheart-Willcox Publisher)

**Changing Inches to Feet** (Goodheart-Willcox Publisher)

**Changing Feet to Inches** Multiply the dimension given in feet by 12 to get the number of inches. (Goodheart-Willcox Publisher)

**Review** Identify each measurement indicated. • 5 1/2 • A. • B. • C. • D. • E. • 4 9/16 • 3 13/16 • 3 1/16 • 1 11/16 (Goodheart-Willcox Publisher)

**Review** Add the following dimensions: A. 6 5/8 + 1 3/4 = B. 3 3/16 + 4 3/4 = C. 2 8 3/8 + 4 6 15/16 = D. 5 4 13/16 + 9 5/8 = • 8 3/8 7 15/16 7 3 5/16 6 2 7/16

**Review** Subtract the following dimensions: A. 9 3/4 – 3 3/8 = B. 1 2 1/4 – 8 1/8 = C. 12 6 3/4 – 7 4 7/8 = D. 6 9 11/16 – 3 10 13/16 = 6 3/8 6 1/8 5 1 7/8 2 10 7/8

**Computing Pipe Offsets** (Goodheart-Willcox Publisher)

**Computing Pipe Offsets** Pythagorean Theorem (Goodheart-Willcox Publisher)

**Computing Pipe Offsets** Pythagorean Theorem (continued) • Pythagorean theorem applies to all right triangles. (Goodheart-Willcox Publisher)

**Computing Pipe Offsets** Trigonometric Functions (Goodheart-Willcox Publisher)

**Computing Pipe Offsets** Trigonometric Functions (continued) • Theoretical Length vs. Actual Length Actual length of pipe = Theoretical length –Laying lengthof fittings (Goodheart-Willcox Publisher)

**Computing Pipe Offsets** Simple Methods (Goodheart-Willcox Publisher)

**Computing Pipe Offsets** Plumber’s Rule (Goodheart-Willcox Publisher)

**Review** • Find the travel of the pipe required to join two pipes at a 45 angle that are offset at each of the following distances: • A. 30 = • B. 18 = • C. 1 3 = • D. 2 9 = 42.42 or 4 7/16 25.45 or 25 7/16 22.21 or 22 1/4 46.66 or 46 11/16

**Computing Area and Volume** Square or Rectangular Surface (Goodheart-Willcox Publisher)

**Computing Area and Volume** Area of Circles (Goodheart-Willcox Publisher)

**Computing Area and Volume** Volume of a Rectangular Tank (Goodheart-Willcox Publisher)

**Computing Area and Volume** Volume of a Cylindrical Tank (Goodheart-Willcox Publisher)

**Review** • Compute the area of the following: • A. 6 6 square = • B. 4 9 12 3 rectangle = • C. 8 6 diameter circle = • D. 4 9 radius circle = 42.25 sq. ft. 58.19 sq. ft. 2,289 sq. in. 10,202 sq. in.

**Review** Compute the volume of these tanks: A.B. 615.44 cu. ft. 63 cu. ft.

**Computing Slope of Pipe** (Goodheart-Willcox Publisher)

**Metric Measurement** Length (Goodheart-Willcox Publisher)

**Metric Measurement** Dry Volume

**Metric Measurement** Liquid Measures

**Metric Measurement** Temperature

**Review** • Identify the metric units of measurement used when measuring: • A. Distance: • B. Liquid volume: • C. Dry volume: • D. Temperature: meter, centimeter, millimeter liter or cubic centimeter cubic meter Celsius or Kelvin

**Review** • Convert each of the following customary measurements to the equivalent metric measurement. • A. Distance: 1 3 • B. Liquid measure: 22 cu. ft. • C. Dry volume: 135 cu. ft. • D. Temperature: 85 F 68.44 cm. 623.04 L 3.77 cu. meters 29.7 Celsius

**End of Chapter 4**