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Find the perimeter of a rectangle whose length is 12 longer than its width
with an area of 45 square feet. To earn 5 points write the mathematical
sentence, the value of Length, width and perimeter

Respuesta :

maniknandini

Answer:

l = 21

w = 9

P = 60

Step-by-step explanation:

l = 12 + w

A = l*w = 45

substitute l = 12 +w

45 = (12 + w) * w

45 = 12w + w^2

w^2 + 12w - 45 = 0

w^2 + 2*6*w +36 = 45 + 36 (added 36 on both sides 6^2)

(w + 6) ^2 = 45+36 = 81

w + 6 = +-9

As width cannot be negative w = 9

so l = 12 + 9

= 21

Perimeter = P = 2 (l + b)

= 2 ( 21 + 9)

= 2 (30)

= 60

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