Exercise 4.4

1. Which of the following are adjacent angles?

(i)

Solution:

a,b are adjacentNot adjacent angles, as they have a common vertex and common arm.

(ii)

Solution:

c,d are adjacentNot adjacent angles, as they have a common vertex and common arm.

(iii)

Solution:

e,f are Not adjacentAdjacent angles, as they not have a common vertex and common arm.

2. Name all pairs of adjacent angles in the figure. How many pairs of adjacent angles are formed? Why these angles are called adjacent angles?

Solution:

∠AOD∠AOB, ∠DOB∠DOC

(ii) ∠DOB∠DOC, ∠BOC∠AOB

(iii) ∠BOC∠DOA, ∠COACOD

(iv) ∠COADOB, ∠AOD∠COD

Those angles are called adjacent angles because they have a common vertex and common arm.

3. Can two adjacent angles be supplementary?Draw figure.

Solution:

YesNo

4. can two adjacent angles be complementary?Draw figure.

Solution:

YesNo

5. Give four examples of adjacent angles in daily life.

Example: Angles between the spokes at the centre of a cycle wheel.

(i) Opening a DoorOpposite Corners of a Room

(ii) Pizza SlicesAngles in Triangle

(iii) Hands of a ClockAngles Formed by Crossed Streets

(iv) Pages in a BookAngles in a Checkerboard