In the parallelogram ABCD, AL and CM are perpendicular to CD and AD respectively. AL = 20 cm, CD = 18 cm and CM = 15 cm. The perimeter of the parallelogram is:

Correct option is B

Given:

In parallelogram ABCD, AL and CM are perpendicular to CD and AD respectively. 

AL = 20 cm, CD = 18 cm and CM = 15 cm

Formula used:

Area of  parallelogram = Base × Height 

Perimeter of parallelogram = 2 × (Sum of parallel sides) 

Solution:

Area of ABCD with base DC = AL × DC = 20 × 18 

= 360 cm²

Again, Area of ABCD with base AD = CM × AD = 15 × AD 

= 360 cm2 =  15 × AD 

So,  AD = 24 cm 

AD = BC = 24 cm, DC = AB = 18 cm 

Perimeter of ABCD = 2 × (24 + 18) 

=> 2 × 42

=> 84 cm