Answer:
The rectangle above shows its dimensions. Find the perimeter.
First, substitute the values for the width
(W)
and the length
(L)
into the perimeter formula.
P=2(12)+2(9)
Next, complete the multiplication and addition to find the perimeter.
PPP===2(12)+2(9)24+1842
The answer is 42.
The perimeter of the rectangle is 42 inches.
Area is the amount of square units inside the figure. Area is found by multiplying the
length×width
. The formula for finding the area of a rectangle is:
A=L×W
You can use the dimensions from the rectangle above to find the area of this rectangle.
First, fill the values for
L
and
W
into the formula for area.
AA==L×W12×9
Next, solve for the area by multiplying.
AA==12×9108
The answer is 108.
The area of the rectangle is
108 in2
.
Notice that the unit of measurement for area is squared. That is because you multiplied a unit measure times itself:
in×in=in2
. Area is always written in square units.
You can also find the perimeter and area of a square. Remember that a square has four equal sides given the symbol
s
. You can use the following formula for finding the perimeter of a square:
P=4s
Let’s look at an example.
A rectangle has a length of 12 feet and a perimeter of 72 feet. Write and solve an equation to determine the width of the rectangle.
First, substitute the values for the perimeter
(P)
and the length
(L)
into the perimeter formula.
72=2(12)+2W
Next, complete the multiplication.
72=24+2W
Then, subtract 24 from both sides to get your variable alone on the right side.
72−2448==24−24+2W2W
Then, multiply both sides by the reciprocal of 2 to isolate your variable.
12×481482W===12×2W1W24
The answer is 24.
The width of the rectangle is 24 feet.
