The perimeter of a rectangular piece of plastic is 30 millimeters. The piece of plastic is 5 millimeters tall. How wide is it?
2(5+w) = 30
To find the width of the rectangular piece of plastic, we can use the formula for the perimeter of a rectangle.
The formula for the perimeter of a rectangle is: P = 2 * (length + width)
In this case, we know that the perimeter is 30 millimeters, and the height (length) is 5 millimeters. Let's substitute these values into the formula:
30 = 2 * (5 + width)
Next, we simplify the equation:
30 = 10 + 2 * width
Now, let's isolate the width by subtracting 10 from both sides of the equation:
30 - 10 = 2 * width
20 = 2 * width
To solve for the width, we divide both sides of the equation by 2:
20 / 2 = width
width = 10
Therefore, the width of the rectangular piece of plastic is 10 millimeters.
2l + 2w = 22
l + w = 11 ---> l = 11 - w
area = 30
lw = 30
(11-w)(w) = 30
11w - w^2 = 30
w^2 - 11w + 30 = 0
(w-5)(w-6) = 0
w = 5 or w = 6
if w = 5 , l = 11-5 = 6
if w = 6, l = 11 - 6 = 5
the dimension is 5 by 6 mm