# Describe different types of Angles

## Lesson Plan of Describe different types of Angles

Students` Learning Outcomes

• Describe adjacent, complementary and supplementary angles.

Information for Teachers

• Adjacent Angles: two angles with common vertex, one common arm and uncommon interior are called Adjacent Angles.

• Angles x and y are adjacent because they share a ray [line in red] and a vertex [point in black called D]
• Complementary Angles:  two angles whose sum of measures is 900 are called Complementary angles.
• Complementary may or may not be adjacent.
• If the angles are not adjacent, still they can be called complementary angles, as given below are complementary angles because the sum of their measures is 900.

• For example the following pairs of non-adjacent angles are also complementary as their sum is equal 900 degrees.

• Supplementary Angles: two adjacent or non-adjacent angles are Supplementary if their sum is equal to 1800 degrees.

• Examples:
• 400and 1400 are supplementary angles of each other.
• 930and 870 are supplementary angles of each other.
• The following pairs of non-adjacent angles are also supplementary angles as their sum is equal to 1800.

• Consult textbook at all the steps wherever required.

Material / Resources

Writing board, chalk / marker, duster, textbook

Introduction

• Ask the students to look for following words in English dictionary [this can be given as home work one day before]
• Inquire the meanings and then introduce one by one.

Development

Activity 1

• Supplementary Angles:
• Ask students to draw a straight line in the notebooks. Take any point on the line and draw another line to form any angle. [Show figure]
• Ask them to measure the angles on both sides and add the degrees of both.
• Raise your hands if you get 1800 as the sum [they all will raise as they finish measurements]
• Tell them that these angles are called supplementary angles.
• Also introduce that supplementary angles are not necessary adjacent. Ask children to make / find some supplementary angles.

Activity 2

• Complementary Angles:
• Ask the students to first draw a right angle and then draw a line starting from its vertex cutting through the right angle making another angle.

• Ask them to measure both the angles and add the degrees and then introduce the term complementary angles.
• Divide the students in groups and ask them to think about the definitions discussed.
• Ask “can we consider following as examples of Supplementary angles, if yes then why?” There are Adjacent angles of a four-cornered room.
• Adjacent angles of a window; Time of 6:00 with the second hand pointed at 3,
• Two adjacent ends of a piece of papers.
• Ask “can we considered following as examples of Complementary angles, if yes then why.
• Adjacent angles of a four-cornered room
• Adjacent angles of a window
• Time of 6:00 with the second hand pointed at 3
• Two adjacent ends of a piece of paper
• Ask ‘can we consider following as examples of Complementary angles, if yes then why?
• Examples of Complementary angles:
• Time of 3:00 with the second hand pointed at 2.
• Wind up the lesson by inviting students one by one in front of class to repeat verbally.

Sum up / Conclusion

• Review new learning with the students.
• Ask them to define the following:
• Adjacent Angles: two angles with common vertex, one common arm and uncommon interior are called Adjacent Angles.
• Complementary Angles: two angles whose sum of measures is 900are called Complementary Angles.
• Supplementary Angles: two angles are supplementary if they add up to 1800 degrees.

Assessment

• Feedback of students on related examples of activities will help to assess them.
• Draw different angles on the board as given in examples and ask them to identify pairs with respect to complementary, supplementary and adjacent.