Question

From the above image, if AB = 35 cm, AD = 20 cm and area of the parallelogram is 560 cm2 find LB.​

Answer 1

Correct option is A)

We have ABCD is a parallelogram with base AB=35 cm and corresponding attitude DL. The adjacent side of the parallelogram AD=20 cm

It is given that the area of the parallelogram ABCD=560 cm

2

Now,

Area of the parallelogram = Base×Height

⇒560 cm

2

=AB×DL

⇒560 cm

2

=35 cm×DLDL=

35 cm

560 cm

2

=16 cm

Again by Pythagoras theorem, we have

(AD)

2

=(AL)

2

+(DL)

2

⇒(20)

2

=(AL)

2

+(16)

2

⇒(AL)

2

=(20)

2

−(16)

2

⇒(AL)

2

=400−256

⇒(AL)

2

=144

⇒AL=12 cm

From the figure AB=AL+LB

⇒35 cm=12 cm+LB

⇒LB=35 cm−12 cm

⇒LB=23cm

Hence, Length of LB is 23 cm