In figure. (i) and (ii), DE || BC. Find EC in (i) and AD in (ii).

In the given figure (i) and (ii), DE || BC. Find EC in (i) and AD in (ii) -  CBSE Class 10 Maths - Learn CBSE Forum

Asked by Pragya Singh | 1 year ago |  65

1 Answer

Solution :-

(i) Given, in △ ABC, DE∥BC

 \( \dfrac{ AD}{DB}=\dfrac{AE}{EC}\) [Using Basic proportionality theorem]

\( \dfrac{1.5}{3}=\dfrac{1}{EC}\)

⇒EC = \( \dfrac{3}{1.5}\)

EC = 3×\( \dfrac{10}{15}\) = 2 cm

Hence, EC = 2 cm.

 

(ii) Given, in △ ABC, DE∥BC

 \( \dfrac{ AD}{DB}=\dfrac{AE}{EC}\) [Using Basic proportionality theorem]

⇒ \( \dfrac{ AD}{7.2}=\dfrac{1.8}{5.4}\)

⇒ AD = 1.8 × \( \dfrac{7.2}{5.4}\)

\( \dfrac{18}{10}×\dfrac{72}{10}×\dfrac{10}{54}=\dfrac{24}{10}\)

⇒ AD = 2.4

Hence, AD = 2.4 cm.

Answered by Abhisek | 1 year ago

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