Find the number of right angles turned through by the hour hand of a clock when it goes from
(a) 3 to 6
(b) 2 to 8
(c) 5 to 11
(d) 10 to 1
(e) 12 to 9
(f) 12 to 6

AcademicMathematicsNCERTClass 6

To do:

We have to find the number of right angles turned through by the hour hand of a clock in each case.

Solution:

We know that,

In one complete clockwise revolution, the hour hand rotates by $360^0$

Therefore,

(a) When the hour hand goes from 3 to 6, it will rotate by $90^0$

Number of right angles $= \frac{90^o}{90^o}$

$=1$

(b) When the hour hand goes from 2 to 8, it will rotate by $180^0$

Number of right angles $= \frac{180^o}{90^o}$

$=2$

(c) When the hour hand goes from 5 to 11, it will rotate by $180^0$

Number of right angles $= \frac{180^o}{90^o}$

$=2$

(d) When the hour hand goes from 10 to 1, it will rotate by $90^0$

Number of right angles $= \frac{90^o}{90^o}$

$=1$

(e) When the hour hand goes from 12 to 9, it will rotate by $270^0$

Number of right angles $= \frac{270^o}{90^o}$

$=3$

(f) When the hour hand goes from 12 to 6, it will rotate by $180^0$

Number of right angles $= \frac{180^o}{90^o}$

$=2$

raja
Updated on 10-Oct-2022 13:32:11

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