LINES ANG ANGLES

2. MEASURE OF ANGLES

The unit measurement of angles is degree, which is denoted by . The measure of the angle for one rotation is .

One full rotation of minute hand of a wall clock is equal to 60 minutes. 1 minute is equal to 60 seconds. You can also find the same thing on degree’s unit.

1 degree = 60 minutes, denoted by 

1 minute = 60 seconds, denoted by 

Example:

Solve the following problems.

1.

2.

3.

4.

5..

SOLUTION:

1. We have    so that .

2. We have   so that .

3. We have  so that .

4. We have   so that .

5. We have    degrees, so that    degrees =.

3. ADDITION AND SUBTRACTION ON ANGLES.

The followings should be considered whenever we want to add and subtract the angles.

• The counterclockwise rotation of an angle results the positive value of its measure.
• The clockwise rotation of an angle results the negative value of its measure.

EXAMPLE:

Determine the result of:

1..

2. .

3..

4..

5.

SOLUTION:

1.= .

2.
=.

3.= 

=.

4. =

=

5.
= 
=
= .