Question

In triangle ABC , DE is parallel to BC , DE is parallel to BC. If AD / BD = 3 / 4 and AC = 15 cm,

find AE

6.4 cm

6 cm

7 cm

5 cm​

Answer 1

$\underline{\underline{\huge{\pink{\tt{\textbf Answer :-}}}}}$

AD/DB =AE/(AC-AE)

3/4=AE/(15-AE)

3(15-AE)=4AE

45=4AE+3AE

45=4AE+3AE

45=7AE

AE=45/7

=6.4

Answer 2

Step-by-step explanation:

Given : DE∥BC in △ ABC,

Using Basic proportionality theorem,

∴

DB

AD

=

EC

AE

⇒

3

1.5

=

EC

1

⇒EC=

1.5

3

EC=3×

15

10

=2 cm

EC=2 cm.

(ii) In △ABC,DE∥BC (Given)

Using Basic proportionality theorem,

∴

DB

AD

=

EC

AE

⇒

7.2

AD

=

5.4

1.8

⇒AD=1.8×

5.4

7.2

=

10

18

×

10

72

×

54

10

=

10

24

⇒AD=2.4cm

So, AD=2.4 cm