The area of a rectangle is calculated by multiplying the length by the width. Here, the length is 7.5 and the width is 2, so the area will be 15. 

Given that the area is also equal to \(\displaystyle 5x\), the value of \(\displaystyle x\) will be 3, given that 3 times 5 is 15. 

Multiply each dimension by \(\displaystyle 100\) to convert meters to centimeters:

\(\displaystyle 4.3 \times 100 = 430\)

\(\displaystyle 3.5 \times 100 = 350\)

Multiply these dimensions to get the area of the rectangle in square centimeters:

\(\displaystyle 430 \times 350 = 150,500\textrm{ cm}^{2}\)

To solve, simply use the formula for the area of a rectangle.

In this particular case the length and width are given,

\(\displaystyle l=6, w=5\).

Thus:

\(\displaystyle area=l*w=6*5=30\)

The area of a rectangle is the length times the width.  So to calculate it, you must multiple the two different lengths together.  Adding the four wall lengths would get you the perimeter instead.

To find the area of a rectangle, we use the following formula:

\(\displaystyle \text{area of rectangle} = l \cdot w\)

where l is the length and w is the width of the rectangle.

Now, given the rectangle,

we can see the length is 12 feet.  We also know the width is half of the length.  Therefore, the width is 6 feet.  Knowing this, we can substitute into the formula.  We get

\(\displaystyle \text{area of rectangle} = 12\text{ft} \cdot 6\text{ft}\)

\(\displaystyle \text{area of rectangle} = 72\text{ft}^2\)

The Smartboard in your math classroom is 3 feet tall and 20 feet long. What is the area of the surface of the Smartboard?

This problem gives us a rectangle and asks us to find the area.

The area of a triangle can be found by the following formula.

\(\displaystyle A=l*w\)

Where l and w are length and width, respectively.

Plug in our length and width and solve.

\(\displaystyle A=3ft*20ft=60ft^2\)

So, we get 60 ft squared for our answer.

Construct an additional segment as shown below.

Note that the figure can be divided into two rectangles. Also note that, since opposite sides of a rectangle are of the same length, we can fill in some sidelengths, as noted above.

The two rectangles each have areas that are the product of their lengths and widths:

\(\displaystyle 10 \times 30 = 300\)

and 

\(\displaystyle 15 \times 30 = 450\)

Add these areas: \(\displaystyle 300 + 450 = 750\), the area of the shape.

You are designing a book cover for a local artist. If the cover will be made from one piece of material that is 14 inches by 8 inches, how much area will the book cover take up?

We are asked to find the area of a rectangle here. 

To find the area of a rectangle simply use the following:

\(\displaystyle A_{rectangle=l*w}\)

So, plug in our length and width

\(\displaystyle A=14in*8in=112in^2\) 

So our answer is 112 inches squared.

A rectangular postage stamp has a width of 3 cm and a height of 12 cm. Find the area of the stamp.

To find the area of  a rectangle, we must perform the following:

\(\displaystyle A_{Rectangle}=l*w\)

Where l and w are our length and width.

This means we need to multiply the given measurements. Be sure to use the right units!

\(\displaystyle A=3cm*12cm=36cm^2\)

And we have our answer. It must be centimeters squared, because we are dealing with area.

To find the area of a rectangle, we will use the following formula:

\(\displaystyle \text{area of rectangle} = l \cdot w\)

where l is the length and w is the width of the rectangle.

Now, we know the length of the rectangle is 8cm.  We also know the width is half the length.  Therefore, the width is 4cm.  Knowing this, we can substitute into the formula.  We get

\(\displaystyle \text{area of rectangle} = 8\text{cm} \cdot 4\text{cm}\)

\(\displaystyle \text{area of rectangle} = 32\text{cm}^2\)