10.2.2 Transformations II, PT3 Focus Practice


Question 6:
Diagram below shows a ‘Wayang Kulit’ performed by Tok Dalang. The height of the screen use is 1.5 m. The shadow on the screen is ⅔ the height of the screen.
What is the height, in cm, of the puppet used by Tok Dalang?

Solution:
Height of shadow = 2 3  of height of screen = 2 3 ×1.5 m =1.0 m Height of puppet Height of shadow = 0.2 0.2+0.6 Height of puppet 1 = 0.2 0.8 Height of puppet =0.25 m =25 cm




Question 7:
Diagram below shows the shadow of a pillar form on the wall from the light of a spotlight. 
(a) State the scale factor of the enlargement.
(b) Find the height of the pillar. 

Solution:
(a)
Scale factor= 2+6 2    = 8 2    =4

(b)
Height of pillar Height of shadow = 1 4 Height of pillar 1.2 = 1 4 Height of pillar= 1 4 ×1.2 m =0.3 m




Question 8:
In diagram below, a torch light is used to form a shadow of a candle on the screen.


The height of the candle is 15 cm.
If the height of the shadow of the candle is ¾ of the height of the screen, find the height of the screen.

Solution:
Height of candle Height of shadow = 30 30+90 15 cm Height of shadow = 1 4 Height of shadow=15 cm×4 =60 cm 3 4  of height of screen=60 cm Height of screen= 4 3 ×60 cm   =80 cm


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