Unit A: Geometry

Chapter 3: Trigonometry

Lesson 1: The Sine Law

Skill Builder

A video demonstrating the use of a proportion to solve a conversion problem is provided.

Example 2

Use the proportion strategy to complete the following conversion.

5 inches =______feet

\frac{y}{5 inches} = \frac{1 foot}{12 inches}

Cross multiply

\begin{array}{rcl} 12 inches \times y & = & 5 (inches) (foot) \\ \frac{12 inches \times y}{12 inches} & = & \frac{5 (inches) (foot)}{12 inches} \\ y & = & 0.417 feet \end{array}

5 inches = 0.417 feet

Example 3

Use the proportion strategy to complete the following conversion.

58 gallons =______quarts

\frac{y}{58 gallons} = \frac{4 quarts}{1 gallon}

Cross multiply.

\begin{array}{rcl} 1 gallon \times y & = & 58 gallons \times 4 quarts \\ \frac{1 gallon \times y}{1 gallon} & = & \frac{58 gallons \times 4 quarts}{1 gallon} \\ y & = & 232 quarts \end{array}

58 gallons = 232 quarts