Question

ABCD is a parallelogram. If perimeter of
parallelogram is 20 cm and AB = x cm, then BC
is equal to
(1) (10 + x) cm
(2) (10 - x) cm
(3) (20 + x) cm
(4) (20 - x) cm​

Answer 1

Question :-

• ABCD is a parallelogram. If perimeter of parallelogram is 20 cm and AB = x cm, then BC is equal to
• (1) (10 + x) cm
• (2) (10 - x) cm
• (3) (20 + x) cm
• (4) (20 - x) cm

Answer

Given :-

• ABCD is a parallelogram.
• Perimeter of a parallelogram is 20 cm.
• AB = x cm.

To Find :-

• Length of BC

Formula used :-

$\ \: \boxed{Perimeter\:of\:Parallelogram=2 \times (a \: + b)}$

where, a and b are adjacent sides of parallelogram.

Solution :-

AB = x cm

Perimeter of parallelogram = 20 cm

⇛ 2 × (AB + BC) = 20

⇛ x + BC = 10

⇛ BC = 10 - x cm

⇛ Option (2) is correct.