How do I draw a rectangle that has the circumference 20cm. The long side should be 4times as long as the short side . Calculate the rectangle's area ?

1 Answer
Feb 5, 2018

Area of rectangle #color(blue)(A = l * w = 16 * 4 = 64)# #color(green)(cm^2#

Explanation:

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Circumference of a rectangle is the same as the perimeter of a rectangle. Normally circumference is used of curved figures and perimeter for the figures formed with straight lines.

Perimeter of a rectangle

#p = 2 (l + w)# where l and w are the lengths and breadths of the rectangle.

Given #P_R = 20 cm, l = 4 * w#

#:. 2 * (l + w) = 2 * (4 w + w) = 20#

#5w = 20# or #w = cancel(20) ^4 / cancel(5) ^1 = 4 cm#

#l = 4 *b = 4 * 4 = 16 cm#

Area of rectangle

#A = l * w = 16 * 4 =color(blue)( 64)# #color(green)(cm^2#