GRE Math : Parallelograms

Study concepts, example questions & explanations for GRE Math

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Example Questions

Example Question #21 : Quadrilaterals

A parallelogram has a base measurement of \(\displaystyle 24\textup{mm}\). The perimeter of the parallelogram is \(\displaystyle 80\textup{mm}\). Find the measurement of an adjacent side to the base. 

Possible Answers:

\(\displaystyle 16\textup{mm}\)

\(\displaystyle 8\textup{mm}\)

\(\displaystyle 36\textup{mm}\)

\(\displaystyle 12\textup{mm}\)

\(\displaystyle 160\textup{mm}\)

Correct answer:

\(\displaystyle 16\textup{mm}\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. This parallelogram must have two sides with a measurement of \(\displaystyle 16\textup{mm}\) and two base sides each with a length of \(\displaystyle 24\textup{mm}\). In this question, you are provided with the information that the parallelogram has a base of \(\displaystyle 24\textup{mm}\) and a total perimeter of \(\displaystyle 80\textup{mm}\). Thus, work backwards using the perimeter formula in order to find the length of one missing side that is adjacent to the base.

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle 80=2(24+b)\)

\(\displaystyle 80=48+2b\)

\(\displaystyle 2b=80-48=32\)

\(\displaystyle b=\frac{32}{2}=16\)

Example Question #22 : Quadrilaterals

A parallelogram has a base of \(\displaystyle 16\). The perimeter of the parallelogram is \(\displaystyle 82\). Find the sum of the two adjacent sides to the base. 

Possible Answers:

\(\displaystyle 25\)

\(\displaystyle 50\)

\(\displaystyle 33\)

\(\displaystyle 41\)

\(\displaystyle 66\)

Correct answer:

\(\displaystyle 50\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. This parallelogram must have two sides with a measurement of \(\displaystyle 25\) and two base sides each with a length of \(\displaystyle 16\). In this question, you are given the information that the parallelogram has a base of \(\displaystyle 16\) and a total perimeter of \(\displaystyle 82\). Thus, work backwards using the perimeter formula in order to find the sum of the two adjacent sides to the base.

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle 82=2(16+b)\)

\(\displaystyle 82=32+2b\)

\(\displaystyle 2b=82-32=50\)

Example Question #4 : How To Find The Length Of The Side Of A Parallelogram

A parallelogram has a base of \(\displaystyle 55\textup{mm}\). An adjacent side to the base has a length of \(\displaystyle 45\textup{mm}\). Find the perimeter of the parallelogram. 

Possible Answers:

\(\displaystyle 150\textup{mm}\)

\(\displaystyle 250\textup{mm}\)

\(\displaystyle 100\textup{mm}\)

\(\displaystyle 175\textup{mm}\)

\(\displaystyle 200\textup{mm}\)

Correct answer:

\(\displaystyle 200\textup{mm}\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. Therefore, this parallelogram must have two sides with a measurement of \(\displaystyle 45\textup{mm}\) and two base sides each with a length of \(\displaystyle 55\textup{mm}\). To find the perimeter of the parallelogram apply the formula: 

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle p=2(55+45)\)

\(\displaystyle p=2(100)\)

\(\displaystyle p=200\)

Example Question #5 : How To Find The Length Of The Side Of A Parallelogram

A parallelogram has a base measurement of \(\displaystyle 140\textup{ inches}\). The perimeter of the parallelogram is \(\displaystyle 46\textup{ feet}\). Find the measurement for an adjacent side to the base. 

Possible Answers:

\(\displaystyle 136\textup{ inches}\)

\(\displaystyle 23\textup{ feet}\)

\(\displaystyle \textup{Not enough information is provided}\)

\(\displaystyle 36\textup{ inches}\)

\(\displaystyle 272\textup{ inches}\)

Correct answer:

\(\displaystyle 136\textup{ inches}\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. Therefore, this parallelogram must have two sides with a measurement of \(\displaystyle 136\textup{ inches}\) and two base sides each with a length of \(\displaystyle 140\textup{ inches}\). However, to solve this problem you must first convert the provided perimeter measurement from feet to inches. Since an inch is \(\displaystyle \frac{1}{12}\) of \(\displaystyle 1\) foot, \(\displaystyle 46\) feet is equal to\(\displaystyle 46\times12=552\) inches.

Now, you can work backwards using the formula: 

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle 552=2(140+b)\)

\(\displaystyle 552=280+2b\)

\(\displaystyle 2b=552-280=272\) 

\(\displaystyle b=\frac{272}{2}=136\)

Example Question #23 : Quadrilaterals

Parallelogram gre

Using the parallelogram shown above, find the length of side \(\displaystyle x.\)

Possible Answers:

\(\displaystyle 16\)

\(\displaystyle 25\)

\(\displaystyle 50\)

\(\displaystyle 32\)

\(\displaystyle 8\)

Correct answer:

\(\displaystyle 16\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. Therefore, this parallelogram must have two sides with a measurement of \(\displaystyle 16\) and two base sides each with a length of \(\displaystyle 18.\) Since the perimeter and one base length is provided in the question, work backwards using the perimeter formula:

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle 68=2(18+b)\)

\(\displaystyle 68=36+2b\)

\(\displaystyle 2b=68-36=32\)

\(\displaystyle b=\frac{32}{2}=16\)

Example Question #1 : How To Find The Length Of The Side Of A Parallelogram

A parallelogram has a base of \(\displaystyle 22\). The perimeter of the parallelogram is \(\displaystyle 72\). Find the sum of the two adjacent sides to the base. 

Possible Answers:

\(\displaystyle 16\)

\(\displaystyle 50\)

\(\displaystyle 14\)

\(\displaystyle 11\)

\(\displaystyle 28\)

Correct answer:

\(\displaystyle 28\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. This parallelogram must have two sides with a measurement of \(\displaystyle 14\) and two base sides each with a length of \(\displaystyle 22\). In this question, you are provided with the information that the parallelogram has a base of \(\displaystyle 22\) and a total perimeter of \(\displaystyle 72\). Thus, work backwards using the perimeter formula in order to find the sum of the two adjacent sides to the base.

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle 72=2(22+b)\)

\(\displaystyle 72=44+2b\)

\(\displaystyle 2b=72-44=28\)

Example Question #141 : Geometry

A parallelogram has a base of \(\displaystyle 28\). An adjacent side to the base has a length of \(\displaystyle 18\). Find the perimeter of the parallelogram. 

Possible Answers:

\(\displaystyle 38\)

\(\displaystyle 92\)

\(\displaystyle 98\)

\(\displaystyle 47.5\)

\(\displaystyle 46\)

Correct answer:

\(\displaystyle 92\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. Therefore, this parallelogram must have two sides with a measurement of \(\displaystyle 18\) and two base sides each with a length of \(\displaystyle 28.\) To find the perimeter of the parallelogram apply the formula: 

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle p=2(28+18)\)

\(\displaystyle p=2(46)\)

\(\displaystyle p=92\)

Example Question #21 : Quadrilaterals

A parallelogram has a base of \(\displaystyle 95\textup{mm}\). The perimeter of the parallelogram is \(\displaystyle 338\textup{mm}\). Find the length for an adjacent side to the base. 

Possible Answers:

\(\displaystyle 148\textup{mm}\)

\(\displaystyle 74\textup{mm}\)

\(\displaystyle 72\textup{mm}\)

\(\displaystyle 42\textup{mm}\)

\(\displaystyle 36\textup{mm}\)

Correct answer:

\(\displaystyle 74\textup{mm}\)

Explanation:

A parallelogram must have two sets of congruent/parallel opposite sides. Therefore, this parallelogram must have two sides with a measurement of \(\displaystyle 74\textup{mm}\) and two base sides each with a length of \(\displaystyle 95\textup{mm}\). To solve for the missing side, work backwards using the perimeter formula: 

\(\displaystyle \textup{Perimeter}=2(a+b)\), where \(\displaystyle a\) and \(\displaystyle b\) are the measurements of adjacent sides. 

Thus, the solution is:

\(\displaystyle 338=2(95+b)\)

\(\displaystyle 338=190+2b\)

\(\displaystyle 2b=338-190=148\)

\(\displaystyle b=\frac{148}{2}=74\)

Example Question #1 : How To Find The Perimeter Of A Parallelogram

A quadrilateral has equal sides, each with a length of \(\displaystyle 4\).

Quantity A: The area of the quadrilateral.

Quantity B: The perimeter of the quadrilateral.

Possible Answers:

The two quantities are equal.

Quantity B is greater.

The relationship cannot be determined.

Quantity A is greater.

Correct answer:

The relationship cannot be determined.

Explanation:

We are told that the shape is a quadrilateral and that the sides are equal; beyond that, we do not know what specific kind of kind of quadrilateral it is, outside of the fact that it is a rhombus. The perimeter, the sum of the sides, is \(\displaystyle 16\).

If this shape were a square, the area would also be \(\displaystyle 16\); however, if the interior angles were not all equivalent, the area would be smaller than this.

The relationship cannot be determined.

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