Question

Q12: The perimeter of a rectangle is 140 CM if the breadth of the rectangle is 20 cm. Find its length also find the area of the rectangle.
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Answer 1

Answer:

P = 2 [l+ b]                                                        Area

140 = 2 [l + b]                                           A = l x b

140 = 2l + 40                                            A = 50 x 20

140 - 40 = 2l                                             A = 1000 sq.cm

100 = 2l

There fore, 100/2 = l

l = 50 cm

Checking if the length is correct or not -

P = 2 [l + b]

P = 2 [ 50 + 20]   substituting the length with the answer we found out.

P = 2 x 70 = 140 cm

therefore in the given Perimeter is -

140 cm = to the perimeter we got after substituting the value of length that is 50 cm.

Substituting meaning is to put the value we got instead of the variable we used.

HOPE IT HELPS YOU....