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Sets Intersection: Intersection Of Three Sets




 
In these lessons, we will learn the intersection of three sets, how to shade regions of Venn Diagrams involving three sets and how to solve problems using the Venn Diagram of three sets (three circles).

Related Topics:
More lessons on Sets, Intersection of Two Sets, Venn Diagrams

Venn Diagrams of three sets

The intersection of three sets X, Y and Z is the set of elements that are common to sets X, Y and Z. It is denoted by XYZ


Example:

Draw a Venn diagram to represent the relationship between the sets

X = {1, 2, 5, 6, 7, 9}, Y = {1, 3, 4, 5, 6, 8} and

Z = {3, 5, 6, 7, 8, 10}

Solution:

We find that XYZ = {5, 6}, X Y = {1, 5, 6},

YZ = {3, 5, 6, 8} and XZ = {5, 6, 7}

For the Venn diagram:

Step 1 : Draw three overlapping circles to represent the three sets.

Step 2 : Write down the elements in the intersection XYZ

Step 3 : Write down the remaining elements in the intersections:

XY, YZ and XZ

Step 4 : Write down the remaining elements in the respective sets.

Again, notice that you start filling the Venn diagram from the elements in the intersection first.




In general, there are many ways that 3 sets may intersect. Some examples are shown below.

How to shade regions of Venn Diagrams involving three sets

Venn Diagrams: Shading Regions with Three Sets, Part 1 of 2
This video shows how to shade regions of Venn Diagrams involving three sets.
Example:
Shade the indicated region:
1) (A ∩ B) ∩ C
2) (A ∪ B) ∩ C
Venn Diagrams: Shading Regions with Three Sets, Part 2 of 2
More example to show to shade regions of Venn Diagrams involving three sets.
Example:
Shade the indicated region:
3) (A ∪ B)' ∩ C
4) (A' ∩ B') ∩ C'


 
Sets: writing an expression for a Venn diagram region
Create an expression to represent the outlines part of the Venn Diagram shown.
Learn about Venn diagrams with three subsets.
Give the elements in (A ∪ B') ∩ C


Solve Problems with 3-Set Venn Diagrams

Venn Diagram Problem with 3 Circles
Use the given information to fill in the number of elements in each region of the Venn Diagram.
This video solves two problems using Venn Diagrams. One with two sets and one with three sets.
Example 1:
150 college freshmen were interviewed.
85 were registered for a math class
70 were registered for an English class
50 were registered for both math and English
1. How many signed up only for a math class?
1. How many signed up only for an English class?
1. How many signed up for math or English?
1. How many signed up for neither math nor English?

Example 2:
100 were students interviewed
28 took PE
31 took Bio
42 took Eng
9 took PE and Bio
10 took PE and Eng
6 took Bio and Eng
4 took all three subjects
How many students took none of the three subjects?
How many students took PE, but not Bio or Eng?
How many students took Gio and PE but not Eng?
Venn Diagrams and Sets
This video shows how to solve a Venn Diagram problem involving three sets.
Example 1: 110 college freshmen were surveyed 25 took physics 45 took biology 45 took mathematics 10 took physics and mathematics 8 took biology and mathematics 6 took physics and biology 5 took all three a. How many students took biology, but neither physics nor mathematics? b. How many students took biology, physics or mathematics? c. How many students did not take any of the three subjects?


 
In this video we go over a basic word problem involving three sets. We use a Venn diagram to answer the series of questions.

Rotate to landscape screen format on a mobile phone or small tablet to use the Mathway widget, a free math problem solver that answers your questions with step-by-step explanations.


You can use the free Mathway widget below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.


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