Unit 3, Lesson 12
Writing and Graphing Inequalities
Accelerated 7
12.1
Warm-up
Estimate Heights
12.2
Activity
How High and How Low Can It Be?
Here is a picture of a person next to a basketball hoop and a ladder. Use the picture to make reasonable estimates for the minimum and maximum heights of the basketball hoop.
-
Complete the first blank in each sentence with an estimate, and complete the second blank with “taller” or “shorter.”
-
I estimate the minimum height of the basketball hoop to be
feet. This means the hoop cannot be
than this height. -
I estimate the maximum height of the basketball hoop to be
feet. This means the hoop cannot be
than this height.
-
-
Use your estimate to write an inequality statement that describes the minimum height of the basketball hoop. Use the variable
to represent the unknown height. -
Use your estimate to write an inequality statement that describes the maximum height of the basketball hoop. Use the variable
to represent the unknown height. -
Suppose a classmate estimated the value of
to be 19 feet. Does this estimate agree with your inequality for the maximum height? Does it agree with your inequality for the minimum height? Explain your reasoning.
12.3
Activity
Stories about 9
-
Your teacher will give you a set of cards containing stories and questions, descriptions of values, math statements, and number lines. Match each story and question with 3 other representations. Be prepared to explain your reasoning.
-
Compare your matching decisions with another group. If you disagree, work to reach an agreement. Then, record your final matching decisions here.
-
A fishing boat can hold fewer than 9 people. How many people can it hold?
-
Description of values:
-
Number line:
- Equation and/or inequality:
-
-
Lin needs more than 9 ounces of butter to make some breadsticks. How many ounces of butter would be enough for the breadsticks?
-
Description of values:
-
Number line:
- Equation and/or inequality:
-
-
A magician will perform her magic tricks only if there are at least 9 people in the audience. For how many people will she perform her magic tricks?
-
Description of values:
-
Number line:
- Equation and/or inequality:
-
-
A scale can measure up to 9 kilograms of weight. What weights can the scale measure?
-
Description of values:
-
Number line:
- Equation and/or inequality:
-
-
Student Lesson Summary
An inequality tells us that one value is less than or greater than another value.
Suppose we know the temperature is less than
The temperature can also be graphed on a number line. Any point to the left of 3 is a possible value for
Here is another example. Suppose a young traveler has to be at least 16 years old to fly on an airplane without an accompanying adult.
If
We can also write an inequality and equation to show possible values for
None
Have a correction or suggestion?
Tell us about a typo, a broken link, or an improvement you’d like to see. We read every submission but can’t reply.
Have a question or need support instead? Visit our Contact Us page to reach our team.