Write a function rule for the perimeter of a rectangle whose length is 6 feet more than its width. What is the perimeter of the rectangle when its width is 12 feet?

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Answer 1 · 2017-10-18T02:19:58

#P = 4w + 12#

The perimeter of the rectangle when #w=12# is #60# feet.

The perimeter of a rectangle is equal to 2 times the length #l# plus 2 times the width #w#.

If we know that #l = w + 6#, then we can substitute this into the equation and simplify it.

#P = 2w + 2l#

#P = 2w + 2(w+6)#

#P = 2w + 2w + 12#

#P = 4w + 12#

This is our function for perimeter. Now, if the width is 12, we can simply plug in #12# to this equation and evaluate it for #P#.

#P = 4(12) + 12#

#P = 48 + 12#

#P = 60#

So the perimeter of the rectangle is 60 feet.

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