SSAT Upper Level Math : Areas and Perimeters of Polygons

Study concepts, example questions & explanations for SSAT Upper Level Math

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Example Questions

Example Question #81 : Areas And Perimeters Of Polygons

Rectangle A has length 40 inches and height  inches; Rectangle B has length 30 inches and height  inches; Rectangle C has height  inches, and its area is the sum of those of the other two rectangles. What is its length?

Possible Answers:

The correct answer is not among the other choices.

Correct answer:

The correct answer is not among the other choices.

Explanation:

The area of a rectangle is the product of the length and its height.

Rectangle A has area  square inches, and Rectangle B has an area of  square inches, so the sum of their areas is  square inches. This is the area of Rectangle C; divide it by height  inches to get a length of

 inches. This answer is not among the given choices.

Example Question #81 : Areas And Perimeters Of Polygons

The perimeter of a rectangle is 490 centimeters. The width of the rectangle is three-fourths of its length. What is the area of the rectangle?

Possible Answers:

Correct answer:

Explanation:

Let  be the length of the rectangle. Then its width is three-fourths of this, or . The perimeter is the sum of the lengths of its sides, or

.

Set this equal to 490 centimeters and solve for :

The length of the rectangle is 140 centimeters; the width is three-fourths of this, or 

 centimeters.

The area is the product of the length and the width:

 square centimeters.

 

Example Question #13 : How To Find The Area Of A Rectangle

A basketball team wants to paint a 4-foot wide border around its court to make sure fans don't get too close to the action. If the court is 94 by 50 feet, and one can of paint can cover 300 square feet, how many cans of paint does the team need to ensure that the entire border is painted? 

(Assume that you cannot buy partial cans of paint.)

Possible Answers:

Correct answer:

Explanation:

We begin this problem by finding the difference of two areas: the larger rectangle bounded by the outer edge of the border and the smaller rectangle that is the court itself.

The larger rectangle is  square feet , and the court is  square feet .

The difference, , repesents the area of the border.

Now we divide this by , which is just a bit over . But since we can't leave  square feet unpainted, we have to round up to  cans of paint.

Example Question #81 : Areas And Perimeters Of Polygons

Box

The above diagram shows a rectangular solid. The shaded side is a square. Give the total surface area of the solid.

Possible Answers:

Correct answer:

Explanation:

A square has four sides of equal length, as seen in the diagram below.

Box 2

All six sides are rectangles, so their areas are equal to the products of their dimensions:

Top, bottom, front, back (four surfaces): 

Left, right (two surfaces): 

The total area: 

Example Question #82 : Areas And Perimeters Of Polygons

Box

The above diagram shows a rectangular solid. The shaded side is a square. In terms of , give the surface area of the solid.

Possible Answers:

Correct answer:

Explanation:

Since a square has four sides of equal length, the solid looks like this:

Box

The areas of each of the individual surfaces, each of which is a rectangle, are the product of their dimensions:

Front, back, top, bottom (four surfaces): 

Left, right (two surfaces): 

The total surface area is therefore 

Example Question #821 : Geometry

Parallelogram

Figure NOT drawn to scale

The above figure shows Rhombus  and  are midpoints of their respective sides. Rhombus   has area 900. 

Give the area of Rectangle .

Possible Answers:

Correct answer:

Explanation:

A rhombus, by definition, has four sides of equal length. Therefore, , and, by the Multiplication Property, . Also, since  and  are the midpoints of their respective sides,  and . Combining these statements, and letting :

Also, both  and  are altitudes of the rhombus; they are congruent, and we will call their common length  (height).

The figure, with the lengths, is below.

Rhombus

The area of the entire Rhombus  is the product of its height  and the length of a base , so

.

 Rectangle  has as its length and width  and , so its area is their product , Since

,

From the Division Property, it follows that

,

and

.

This makes 450 the area of Rectangle 

 

Example Question #81 : Areas And Perimeters Of Polygons

A parallelogram has the base length of and the altitude of . Give the area of the parallelogram.

Possible Answers:

Correct answer:

Explanation:

The area of a parallelogram is given by:

 

 

Where is the base length and is the corresponding altitude. So we can write:

 

Example Question #2 : Area Of A Parallelogram

A parallelogram has a base length of  which is 3 times longer than its corresponding altitude. The area of the parallelogram is 12 square inches. Give the .

Possible Answers:

Correct answer:

Explanation:

Base length is so the corresponding altitude is  .

 

The area of a parallelogram is given by:

 

 

Where:


is the length of any base
is the corresponding altitude

 

So we can write:

 

Example Question #2 : Area Of A Parallelogram

The length of the shorter diagonal of a rhombus is 40% that of the longer diagonal. The area of the rhombus is . Give the length of the longer diagonal in terms of .

Possible Answers:

Correct answer:

Explanation:

Let  be the length of the longer diagonal. Then the shorter diagonal has length 40% of this. Since 40% is equal to , 40% of  is equal to .

The area of a rhombus is half the product of the lengths of its diagonals, so we can set up, and solve for , in the equation:

 

Example Question #1 : Area Of A Parallelogram

The length of the shorter diagonal of a rhombus is two-thirds that of the longer diagonal. The area of the rhombus is  square yards. Give the length of the longer diagonal, in inches, in terms of .

Possible Answers:

Correct answer:

Explanation:

Let  be the length of the longer diagonal in yards. Then the shorter diagonal has length two-thirds of this, or .

The area of a rhombus is half the product of the lengths of its diagonals, so we can set up the following equation and solve for :

To convert yards to inches, multiply by 36:

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