Create New Account
Create New Account

Sign in to Innings2

or

New Account     Reset Password     

Understanding Elementary Shapes

    Angles – ‘Right’ and ‘Straight’

    Angles – ‘Acute’, ‘Obtuse’ and ‘Reflex’

    Exercise 5.2

    What Have We Discussed ?

Powered by Innings 2

Reset Progress

This will delete your progress and chat data for all chapters in this course, and cannot be undone!

Glossary

Select one of the keywords on the left…

6th class > Understanding Elementary Shapes > Exercise 5.2

Exercise 5.2

1. What fraction of a clockwise revolution does the hour hand of a clock turn through, when it goes from:

a

(a) 3 to 9

Solution:

We move hours.

The total angle turned through is 6 × ° = °

Fraction: 180°360° =

b

(b) 4 to 7

We move hours.

The total angle turned through is 3 × ° = °

Fraction: 90°360° =

c

(c) 12 to 9

We move hours.

The total angle turned through is 9 × ° = °

Fraction: 270°360° =

d

(d) 1 to 10

We move hours.

The total angle turned through is 9 × ° = °

Fraction: 270°360° =

2. Where will the hand of a clock stop if it:

Clock hand

Where(a) starts at 12 and makes 12 of a revolution clockwise?

We calculate the position by multiplying the fraction of the revolution by 12 (as one revolution has 12 hours).

12 × 12 = hrs

Starting at 12 and moving by 6 divisions clockwise brings us to the number .

Clock hand

Where(b) starts at 2 and makes 12 of a revolution clockwise?

12 × 12 = hrs

Starting at 2 and moving 6 divisions clockwise brings us to the number .

3. Which direction will you face if you start facing:

a

(a) East and make 1/2 of a revolution clockwise ?

1 revolution = ° degrees

12 revolution = ° degrees

Thus, we start from East, move 180 degrees clockwise and stop at .

b

(b) West and make 3/4 of a revolution anti-clockwise ?

34 revolution = ° degrees

(34 = 12 revolution + 14 revolution (180° + 90°))

Thus, we start from West, and stop at .

c

(c) South and make one full revolution ?

Thus, after 1 complete revolution that is °, we stop at the same point from where we had started i.e, .

4. What part of a revolution have you turned through if you stand facing:

Instructions:

14 revolution = 90°

12 revolution = 180°

34 revolution = 270°

a

(a) east and turn clockwise to face north ?

Starting from East and turning clockwise to North involves a ° turn

Therefore 270°360° = revolution.

b

(b) south and turn clockwise to face east ?

Starting from South and turning clockwise to East involves a ° turn.

Therefore 90°360° = revolution.

c

(c) west and turn clockwise to face east ?

Starting from West and turning clockwise to East involves a ° turn.

Therefore 180°360° = revolution.

5. Find the number of right angles turned through by the hour hand of a clock when it goes from:

a

(a) 3 to 6

Number of Hours : - = hrs i.e. Right angle(s).

b

(b) 2 to 8

Number of Hours : - = hrs i.e. Right angle(s).

c

(c) 5 to 11

Number of Hours : - = hrs i.e. Right angle(s).

d

(d) 10 to 1

Number of Hours : + = hrs i.e. Right angle(s).
  1. How many right angles do you make if you start facing:

(a) south and turn clockwise to west :

(b) north and turn anti-clockwise to east :

(c) west and turn to west:

  1. Where will the hour hand of a clock stop if it starts.

Each hour on the clock represents 360°12 = 30°

a

(a) from 6 and turns through 1 right angle ?

1 right angle = °

Since each hour is 30° : 90°30° = Hours

Starting from 6 + 3 hrs =

b

(b) from 8 and turns through 2 right angles ?

2 Right angles = 90° x 2 = °

180° corresponds to 180°30 = Hours.

Starting from + hrs =

Clock resets after 12: 14 - 12 =

c

(c) from 10 and turns through 3 right angles ?

3 Right angles = 90 x 3 = °

270° corresponding to 270°30 = Hours.

Start from + =

Clock resets after 12 : 19 - =