The length of a rectangle is 3 centimeters more than 3 times the width. If the perimeter of the rectangle is 46 centimeters, find the dimension of the rectangle.
a) L = 5cm; W = 18cm
b) L = 13cm; W = 8cm
c) L = 13cm; W = 5cm
d) L = 18cm; W = 5cm
L = Length
W = Width
The length of a rectangle is 3 centimeters more than 3 times the width. If the perimeter of the rectangle is 46 centimeters, find the dimension of the rectangle.
Call the length L and call the width W
Here's the relationship between their sizes: L = 3W + 3
The perimeter is two times the length plus two times the width
So ... 2(L) + 2(W) = 46
Remember L = 3W + 3 so substitute it in the place of L 2(3W + 3) + 2(W) = 46
Multiply it out 6W + 6 + 2W = 46
Combine like terms 8W + 6 = 46
Subtract 6 from each side 8W = 40
Divide both sides by 8 W = 5
Plug this back into L = 3W +3 L = 3(5) + 3 = 15 + 3
L = 18
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