## EXERCISE 17D

1. In Fig. 1 name the following angles

(i) an acute angle at T

(ii) an acute angle at Q

(iii) three obtuse angles

(iv) a right angle

(v) a straight angle

2. Classify the angles whose magnitudes are given below

(i) 132

(ii) 26

(iii) 170

(iv) 30

(v) 79

(vi) 17.5

(vii) 98.7

(viii) 320

(ix) 90

(x) 0

(xi) 180

(xii) 270

3. Find the number of degrees in

(i) of a right angle

(ii) 40% of a right angle

(iii) 120% of a right angle

(iv) of a straight angle

(v) 50% of straight angles

(vi) 130% of a straight angles

4. State the type of angle in each case , formed between the following directions

(i) East and North

(ii) East and West

(iii) North and South-East

(iv) North and North-East

5. Using only a ruler , draw an acute angle , a right angle and an obtuse angle in your notebook and name them .

6. In Fig. Q.6 , find x . Is it acute , obtuse or reflex ?

7. What is the size of the reflex angle between the hands of a clock at 4’O clock , 3’O clock and 10’O clock ?

Exercise 17E

1. Find the value of x in each of the following diagrams

2. In the given Fig.Q.2 , if POR = 100 , find the value of QOR

3. Find the value of x in fig. Q.3

4. Refer to Fig.Q.4 , copy and complete the table

5. In the given Fig.Q.5 , two straight lines intersect at O , copy and complete the following table beside the figure .

6. In the given Fig.Q.6 , find the number of degrees in

(i) (a) 1 (b) 2 (c) 3

(ii) (a) 4 (b) 5

(iii) (a) 6 (b) 7

7. Complete the following tables.

8. (i) Find the measure of an angle which is 20 less than its complement

(ii) Find the measure of the angle , whcih is four times its compliment

9. (i) Find the angles when two angles are supplementary and the larger is 58 more than the smaller

(ii) Two angles are supplementary and the larger is 40 less than three times the smaller . Find the smaller angle .

10. Write ‘T’ for True or ‘F’ for False .

(i) Adjacent angles can be complementary .

(ii) Adjacent supplementary angles always form a linear pair .

(iii) Two supplementary angles always form a linear pair .

(iv) If two lines intersect , then one pair of vertically opposite angles always consists of acute angles and the other obtuse angles .

(v) Two adjacent angles are always supplementary .

(vi) Angles of a linear pair are always supplementary .

Exercise 18A

1. Identify parallel line segments in each of the figures given below:

2. Classify the following as vertical , horizontal or oblique.

(i) The bottom edge of a door .

(ii) A soldier standing in the attention position .

(iii) The hand rail of a staircase.

(iv) A ladder leaning against a wall .

(v) The hinged edge of a door .

(vi) Horizon at sea .

3. In which palne do the wheels of a moving bike revolve ?

4. Based on the adjacent fig, name the following .

(i) All horizontal lines

(ii) All vertical lines

(iii) All vertical planes

(iv) All horizontal planes

(v) All lines perpendicular to DC

EXERCISE 18B

1. Lines l is a transversal to lines n and m . Name the following .

(i) A pair of interior angles on the same side of the transversal

(ii) A pair of exterior angles on the same side of transversal

(iii) Two pairs of alternate interior angles .

(iv) Four pairs of corresponding angles

2. In the figre , write the name of

(i) Alternate interior angles

(ii) Corresponding angles

(iii) Vertical angles

(iv) Co-interior angles with respect to both the transversals PQ and PR

EXERCISE 18C

1. If m||n and 1 = 20 , find the measures of angles

2 , 3 , 4 , 5 , 6 , 7 and 8

2. Find the value of each one of the lettered angles giving reasons

(i)

(ii)

(iii)

(iv)

3. Find the value of each one of the lettered angles giving reasons

(i)

(ii)

(iii)

(iv)

4. Find each of the lettered angles giving reasons .

(i)

(ii)

(iii)

(iv)

5. Find each of the lettered angles giving reasons

(i)

(ii)

(iii)

EXERCISE 19A

1. Draw line segments equal to the following line segments

(i)

(ii)

(iii)

(iv)

2. Draw line segments having these lengths . Use ruler and compasses to bisect each of them .

(i)

(ii)

(iii)

(iv)

3. Draw a line segment AB = 10 cm long . Use ruler and compasses to divide AB into 4 equal parts . What is the length of each part ?

4. Draw a line segment AB of length 4.8 cm . Now , construct the perpendicular bisector of the line segment AB.

5. Draw a line segment of length 6.8 cm and draw its perpendicular bisector by using ruler and compasses .

6. Using a protector , construct an angle of 75 . Now , using a ruler and a pair of compasses , construct an angle equal to 75 .

7. Draw an angle of 135 , using a pair of compasses .

8. With compasses and a ruler , construct each of the following angles.

(i)

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

9. Using your protractor , draw an angle BAC of measure 12. . With this angle as