Games
Problems
Go Pro!

Using Formulas to Solve Word Problems

Reference > Mathematics > Algebra > Basic Word Problems
 

Students sometimes think, "Oh no! Formulas! I hate formulas!" But really, formulas are designed to make life easier for you. Because if you didn't have a formula to use, you'd have to do a lot more work to get an answer. Formulas can help us do a wider range of problems. Here are a few formulas, with explanations:

P = 4s

The perimeter of a square is 4 times the length of a side.

P = 2W + 2L

The perimeter of a rectangle is twice the width plus twice the length.

F = 1.8C + 32

The temperature in Fahrenheit is 1.8 times the temperature in Celsius, plus 32.

d = rt

Distance traveled is the rate (speed) times the amount of time traveled.

A = 1/2(bh)

The area of a triangle is one half the base times the height.

C = 2πr

The circumference of circle is two times pi times the radius.

A + B + C = 180

The sum of the measures of the angles in a triangle is 180 degrees.

Here are some sample problems. These problems use the formulas shown above.

Sample #1

If the perimeter of a square is 48 units, what is the length of a side?

Solution #1

P = 4s, so 48 = 4s, and the answer is s = 12

Sample #2

A car travels 400 miles in 5 hours. How fast is it driving?

Solution #2

d = rt, so 400 = 5r, so r = 80

Questions

1.
The side of a square is 15. What is the perimeter?
2.
If the temperature is 50 degrees F, what is it in Celsius?
3.
If the width of a rectangle is 10, and its perimeter is 50, what is its length?
4.
At what temperature are the Celsius reading and the Fahrenheit reading equal?
5.
If the area of a triangle is 42 square units, and its height is 7 units, what is the length of its base?
6.
If a car travels 200 miles at a rate of 40 mph, how long did it take?
7.
The circumference of a circle is 50.26548. What is its radius?
8.
The width of a rectangle is 12 units, and its length is 4 less than its width. What is its perimeter?
9.
The angles in a triangle are x, 2x, and 3x. What is the measure of the triangle's largest angle?
10.
The angles in a triangle are x, x + 10, and 3x. What is the measure of the triangle's smallest angle?
Assign this reference page
Click here to assign this reference page to your students.
Solving EquationsSolving Equations
Unit IndexUnit Index
 

Blogs on This Site

Reviews and book lists - books we love!
The site administrator fields questions from visitors.
Like us on Facebook to get updates about new resources
Home
Pro Membership
About
Privacy