# SSAT Upper Level Math : How to find the area of a rectangle

## Example Questions

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### Example Question #1 : How To Find The Area Of A Rectangle

Mark wants to seed his lawn, which measures 225 feet by 245 feet. The grass seed he wants to use gets 400 square feet of coverage to the pound; a fifty-pound bag sells for $45.00, and a ten-pound bag sells for$13.00. What is the least amount of money Mark should expect to spend on grass seed?

Explanation:

The area of Mark's lawn is . The amount of grass seed he needs is  pounds.

He has two options.

Option 1: he can buy three fifty-pound bags for

Option 2: he can buy two fifty-pound bags and four ten-pound bags for

The first option is the more economical.

### Example Question #72 : Areas And Perimeters Of Polygons

The width and height of a rectangle are  and , respectively. Give the area of the rectangle in terms of .

Explanation:

The area of a rectangle is given by multiplying the width times the height. As a formula:

Where:

is the width and is the height. So we can get:

### Example Question #73 : Areas And Perimeters Of Polygons

The base length of a parallelogram is equal to the side length of a square. The base length of the parallelogram is two times longer than its corresponding altitude. Compare the area of the parallelogram with the area of the square.

Explanation:

The area of a parallelogram is given by:

Where is the base length and is the corresponding altitude. In this problem we have:

or

So the area of the parallelogram would be:

The area of a square is given by:

weher is the side length of a square. In this problem we have , so we can write:

Then:

or:

### Example Question #1 : How To Find The Area Of A Rectangle

How many squares with the side length of 2 inches can be fitted in a rectangle with the width of 10 inches and height of 4 inches?

Explanation:

Solution 1:

We can divide the rectangle width and height by the square side length and multiply the results:

rectangle width square length =

rectangle heightsquare length =

Solution 2:

As the results of the division of rectangle width and height by the square length are integers and do not have a residual, we can say that the squares can be perfectly fitted in the rectangle. Now in order to find the number of squares we can divide the rectangle area by the square area:

Rectangle area = square inches

Square area = square inches

So we can get:

### Example Question #1 : How To Find The Area Of A Rectangle

A rectangle has the area of 80 square inches. The width of the rectangle is 2 inches longer that its height. Give the height of the rectangle.

Explanation:

The area of a rectangle is given by multiplying the width times the height. That means:

where:

width and  height.

We know that: . Substitube the  in the area formula:

Now we should solve the equation for :

The equation has two answers, one positive  and one negative . As the length is always positive, the correct answer is inches.

### Example Question #1 : How To Find The Area Of A Rectangle

A rectangle with a width of 6 inches has an area of 48 square inches. Give the sum of the lengths of the rectangle's diagonals.

Explanation:

A rectangle has two congruent diagonals. A diagonal of a rectangle divides it into two identical right triangles. The diagonal of the rectangle is the hypotenuse of these triangles. We can use the Pythagorean Theorem to find the length of the diagonal if we know the width and height of the rectangle.

where:

is the width of the rectangle
is the height of the rectangle

First, we find the height of the rectangle:

So we can write:

inches

As a rectangle has two diagonals with the same length, the sum of the diagonals is inches.

### Example Question #1 : How To Find The Area Of A Rectangle

A rectangle has the width of  and the diagonal length of . Give the area of the rectangle in terms of .

Explanation:

First we need to find the height of the rectangle. Since the width and the diagonal lengths are known, we can use the Pythagorean Theorem to find the height of the rectangle:

So we have:

So we can get:

### Example Question #78 : Areas And Perimeters Of Polygons

The perimeter of a rectangle is 800 inches. The width of the rectangle is 60% of its length. What is the area of the rectangle?

Explanation:

Let  be the length of the rectangle. Then its width is 60% of this, or . The perimeter is the sum of the lengths of its sides, or

; we set this equal to 800 inches and solve for :

The width is therefore

.

The product of the length and width is the area:

square inches.

### Example Question #79 : Areas And Perimeters Of Polygons

Rectangle A has length 40 inches and height 24 inches. Rectangle B has length 30 inches and height 28 inches. Rectangle C has length 72 inches, and its area is the mean of the areas of the other two rectangles. What is the height of Rectangle C?

Explanation:

The area of a rectangle is the product of the length and its height, Rectangle A has area  square inches; Rectangle B has area  square inches.

The area of Rectangle C is the mean of these areas, or

square inches, so its height is this area divided by its length:

inches.

### Example Question #80 : Areas And Perimeters Of Polygons

The area of a rectangle is  square feet. The width of the rectangle is four-sevenths of its length. Give the length of the rectangle in inches in terms of .