Q: In the following circles, the end points of $\frac{1}{2}$, $\frac{1}{4}$ and $\frac{1}{8}$ turns are shown. Draw arrows to show the starting points.

$\frac{1}{2}$ turn means the arrow points in the exact opposite direction from where it started. So, if the starting arrow pointed up, after a $\frac{1}{2}$ turn, it points down.Divide the circle into 8 equal parts. Now, turn the arrow by $\frac{1}{8}$ to the left of the end point to get the starting point.Divide the circle into 8 equal parts. Now turn the arrow by two $\frac{1}{8}$ anti-clockwise to the left of the end points to get the starting point.NCERT Textbook Pages 38-40Let Us Do

Q: Guess the measure of turns the minute hand of a clock makes in each of the following cases. The initial position of the minute hand is given. Draw the final position of the minute hand on the clock face. Discuss your reasoning in class. (a) When the minute hand moves by 15 minutes, it has made a _______ turn of the circle.

When the minute hand moves by 15 minutes, it has made a $\frac{1}{4}$ turn of the circle.(b) When the minute hand moves by 30 minutes, it has made a _______ turn of the circle.Solution:When the minute hand moves by 30 minutes, it has made a $\frac{1}{2}$ turn of the circle.(d) When the minute hand has turned by $\frac{1}{12}$ of a full turn, it has moved by ______ minutes.Solution:When the minute hand has turned by $\frac{1}{12}$ of a full turn, it has moved by ______ minutes.(e) When the minute hand has turned a full-circle, it has moved by ______ minutes.Solution:When the minute hand has turned a full-circle, it has moved by $\frac{3}{4}$ minutes.(f) When the minute hand has turned by $\frac{1}{6}$ of a full turn, it has moved by _____ minutes.Solution:When the minute hand has turned by $\frac{1}{6}$ of a full turn, it has moved by 60 minutes.(g) When the minute hand has turned by $\frac{4}{12}$ of a full turn, it has moved by _____ minutes.Solution:When the minute hand has turned by $\frac{4}{12}$ of a full turn, it has moved by 20 minutes.NCERT Textbook Page 40Which direction?The creatures below have made a quarter turn once. Tick the direction in which they have movedTry theseObserve the direction of movement while opening a tap, unscrewing a lid or loosening a nut. Do they move clockwise or anti-clockwise?Solution:Direction of movement while:Opening a tab → Anti-clockwiseUnscrewing a lid or loosening a nut → Anti¬clockwiseNCERT Textbook Pages 40-41Fun with Turns

Question 1

In the following circles, the end points of $\frac{1}{2}$, $\frac{1}{4}$ and $\frac{1}{8}$ turns are shown. Draw arrows to show the starting points.

Accepted Answer

$\frac{1}{2}$ turn means the arrow points in the exact opposite direction from where it started. So, if the starting arrow pointed up, after a $\frac{1}{2}$ turn, it points down.Divide the circle into 8 equal parts. Now, turn the arrow by $\frac{1}{8}$ to the left of the end point to get the starting point.Divide the circle into 8 equal parts. Now turn the arrow by two $\frac{1}{8}$ anti-clockwise to the left of the end points to get the starting point.NCERT Textbook Pages 38-40Let Us Do

Question 2

Measure each angle in the given shapes. Writ.e the measure of the angles in terms of turns and describe whether they are acute, obtuse or right angles.

Accepted Answer

(a) In the given figure, angles A are B’ show turn of less than $\frac{1}{4}$, so they both are acute angles.(b) In the given figure, angles D and D’ show a turn of less than $\frac{1}{4}$. So, angles D and D’ are acute angles.Angle E opens wider than $\frac{1}{4}$ turn but less than a half turn, so angle E is an obtuse angle.(c) In the given figure, only F shows a turn of less than $\frac{1}{4}$, so angle F is an 4 acute angle and angle F’ shows a $\frac{1}{4}$ turn, so angle F’ is a right F angle.Angle G opens wider than $\frac{1}{4}$ turn but less than a $\frac{1}{2}$ turn, so angle G is an obtuse angle.

Question 3

Guess the measure of turns the minute hand of a clock makes in each of the following cases. The initial position of the minute hand is given. Draw the final position of the minute hand on the clock face. Discuss your reasoning in class.
(a) When the minute hand moves by 15 minutes, it has made a _______ turn of the circle.

Accepted Answer

When the minute hand moves by 15 minutes, it has made a $\frac{1}{4}$ turn of the circle.(b) When the minute hand moves by 30 minutes, it has made a _______ turn of the circle.Solution:When the minute hand moves by 30 minutes, it has made a $\frac{1}{2}$ turn of the circle.(d) When the minute hand has turned by $\frac{1}{12}$ of a full turn, it has moved by ______ minutes.Solution:When the minute hand has turned by $\frac{1}{12}$ of a full turn, it has moved by ______ minutes.(e) When the minute hand has turned a full-circle, it has moved by ______ minutes.Solution:When the minute hand has turned a full-circle, it has moved by $\frac{3}{4}$ minutes.(f) When the minute hand has turned by $\frac{1}{6}$ of a full turn, it has moved by _____ minutes.Solution:When the minute hand has turned by $\frac{1}{6}$ of a full turn, it has moved by 60 minutes.(g) When the minute hand has turned by $\frac{4}{12}$ of a full turn, it has moved by _____ minutes.Solution:When the minute hand has turned by $\frac{4}{12}$ of a full turn, it has moved by 20 minutes.NCERT Textbook Page 40Which direction?The creatures below have made a quarter turn once. Tick the direction in which they have movedTry theseObserve the direction of movement while opening a tap, unscrewing a lid or loosening a nut. Do they move clockwise or anti-clockwise?Solution:Direction of movement while:Opening a tab → Anti-clockwiseUnscrewing a lid or loosening a nut → Anti¬clockwiseNCERT Textbook Pages 40-41Fun with Turns

Question 4

Padma is facing the toy shop. What place will she face if she takes a half turn clockwise?
What other way can she turn to face the same place?

Accepted Answer

Since, Padma is facing toy shop, a half turn clockwise means Padma will face the opposite direction. So, she will now face the Ice Cream cart.She can also take a half turn anti-clockwise to face the same place i.e., Ice Cream cart.

Angles as Turns