Formulas Help

By — McGraw-Hill Professional
Updated on Sep 22, 2011


In mathematics and science, many problems can be solved using formulas . A formula is a mathematical statement of a relationship of two or more variables. For example, the relationship between Fahrenheit temperature and Celsius temperature can be expressed by the formula Formulas . Formulas can be evaluated in the same way as expressions are evaluated:

i.e., substitute the values of the variables in the formula and simplify using the order of operations.


Example 1

Find the Fahrenheit temperature corresponding to a Celsius temperature of –10°. Use the formula Formulas

Solution 1


Hence, a Celsius temperature of –10° is equivalent to a Fahrenheit temperature of 14°.

Example 2

Find the interest on a loan whose principal (P) is $3,000 with a rate (R) of 6% for 3 years (T). Use I = PRT.

Solution 2


Formulas Practice Problems


1. Find the distance (D) in miles an automobile travels in 3 hours (T) at a rate (R) of 40 miles per hour. Use D = RT.

2. Find the Celsius (C) temperature when the Fahrenheit (F) temperature is 77°. Use Formulas .

3. Find the volume (V) in cubic inches of a cube when the length of a side (s) is 6 inches. Use V = s 3 .

4. Find the perimeter (P) (distance around the outside) of a rectangle if the length (l) is 6 feet and the width (w) is 4 feet. Use P = 2l + 2w.

5. Find the current (I) in amperes when the electromotive force (E) is 12 volts and the resistance (R) is 3 ohms. Use I = Formulas


1. 120 miles

2. 25°

3. 216 cubic inches

4. 20 feet

5. 4 amperes

Practice problems for this concept can be found at: Expressions And Equations Practice Test.

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