Q16 of 168 Page 5

If such that AB = 5 cm, area () = 20 cm2 and area () = 45 cm2 , determine DE.

We have


ABCDEF


Where AB= 5cm


Area () =20cm2


Area () =45cm2


By area of similar triangle theorem


Area () =AB2


Area () DE2


52/DE2=20/25


25/DE2=4/9


5/DE=2/3


DE=3x5/2


DE=7.5 cm


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