KnowledgeBoat Logo

Mathematics

In figure (1) given below, the perimeter of the parallelogram is 42 cm. Calculate the lengths of the sides of the parallelogram.

In figure (1) given below, the perimeter of the parallelogram is 42 cm. Calculate the lengths of the sides of the parallelogram. Theorems on Area, ML Aggarwal Understanding Mathematics Solutions ICSE Class 9.

Theorems on Area

14 Likes

Answer

Let AB = p

Since, opposite sides of || gm are equal.

Perimeter of || gm ABCD = 2(AB + BC)

⇒ 42 = 2(p + BC)

⇒ p + BC = 422\dfrac{42}{2}

⇒ p + BC = 21

⇒ BC = 21 – P

area of ||gm ABCD = base × height = AB × DM = p × 6 = 6p …….(i)

Also, area of ||gm ABCD = BC × DN

= (21 – p) × 8

= 8(21 – p) ………… (ii)

From (i) and (ii), we get

⇒ 6p = 8(21 – p)

⇒ 6p = 168 – 8p

⇒ 6p + 8p = 168

⇒ 14p = 168

⇒ p = 16814\dfrac{168}{14} = 12 cm.

⇒ 21 - p = 21 - 12 = 9 cm.

Hence, the sides of ||gm are AB = 12 cm and BC = 9 cm.

Answered By

9 Likes


Related Questions