Page 113 - Start Up Mathematics_6

6. Classify the following angles as acute, obtuse, right, straight, zero, reflex or complete angles:
10°, 135°, 0°, 130°, 270°, 180°, 90°, 250°, 179.5°, 55°
7. State the type of angles along with their measure on the following clock faces:

(a) (b) (c) (d)

Thinking Skills

1. Can a triangle have sides of measure 3 cm, 4 cm and 7 cm? Give reasons.
2. Can an angle of an obtuse-angled triangle measure 1°?
3. Two sides of an isosceles triangle measure 3 cm and 8 cm. Find the measure of the third side.
4. If a point lies outside the line. How many line(s) can be drawn through this point (a) parallel
to the given line, (b) perpendicular to the given line?
5. What is an isosceles trapezium? Find the measure of fourth side of the isosceles trapezium
if three of its consecutive sides are 4 cm, 5 cm and 10 cm respectively.
6. Find the sum of the angles of an octagon.
7. State the measure of the unknown angles x and y in each case.
6 9
8 1
5 1

(a) y x (b) 7 y 2

4 2 x
6 3

3 5 4

Some NCERT Textbook Questions

1. If B is the mid point of AC and C is the mid point of BD, where A, B, C, D lie on a straight
line, say why AB = CD?
2. What fraction of a clockwise revolution does the hour hand of a clock turn through, when
it goes from
(a) 3 to 9 (b) 4 to 7 (c) 7 to 10

(d) 12 to 9 (e) 1 to 10 (f) 6 to 3
3. What part of a revolution have you turned through if you stand facing
(a) east and turn clockwise to face north?

(b) south and turn clockwise to face east?
(c) west and turn clockwise to face east?

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