Q4 of 16 Page 149

The picture below shows the parallelogram formed by the intersection of two pairs of parallel lines?


What is the area of this parallelogram? And the perimeter?

Let ABCD is a parallelogram is formed by two set of parallel lines.

The distance between the two horizontal lines is 3 cm,


The distance between the vertically slanted lines is 2 cm.



Connect the two vertically slanted lines a right-angle triangle is formed.


From the right-angle triangle ABE



AB is the hypotenuse


AE is the opposite side


EB is the Adjacent side to θ


Sin θ = =


θ = 30o


ABE is 30o


From the fig. we can say that C = ABE = 30o


In parallelogram opposite sides are equal


BAD = C


BAD = 30o


BAF = 90o


BAF = BAD + DAF


90o = 30o + DAF


DAF = 60o



From the diagram cos θ =


COS 60o =


DA = 6 cm


We know that AD, AB are the sides of the parallelogram


Perimeter = 2 (AB + AD)


= 2 (4+6)


= 20 CM


Area = side × perpendicular distance to the opposite side


= AB × AF


= 4 × 3 = 12 cm2


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