GRE Math : GRE Quantitative Reasoning

Study concepts, example questions & explanations for GRE Math

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Example Questions

Example Question #53 : Geometry

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Find the perimeter of the acute Isosceles triangle shown above. 

Possible Answers:

Correct answer:

Explanation:

To solve this problem apply the formula: .

However, first calculate the length of the missing side by:







Example Question #1 : Triangles

An obtuse Isosceles triangle has two sides with length  and one side length . The length of side   ft. If the length of  half the length of side , what is the perimeter of the triangle? 

Possible Answers:

 ft

 ft

 ft

 ft

Correct answer:

 ft

Explanation:

By definition, an Isosceles triangle must have two equivalent side lengths. Since we are told that  ft and that the sides with length  are half the length of side , find the length of  by:  and half of . Thus, both of sides with length  must equal  ft. 

Now, apply the formula: .



Then, simplify the fraction/convert to mixed number fraction:



 

Example Question #1 : Triangles

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Find the perimeter of the acute Isosceles triangle shown above. 

Possible Answers:

Correct answer:

Explanation:

In order to solve this problem, first find the length of the missing sides. Then apply the formula: 

Each of the missing sides equal: 

 

Then apply the perimeter formula:

Example Question #1 : How To Find The Perimeter Of An Acute / Obtuse Isosceles Triangle

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An acute Isosceles triangle has two sides with length  and one side length . The length of side   inches. If the length of  , what is the perimeter of the triangle? 

Possible Answers:

 inches

 inches

 inches

 inches

Correct answer:

 inches

Explanation:

In order to solve this problem, first find the length of the missing sides. Then apply the formula: 

The missing side equals:



Then plug each side length into the perimeter formula:



 

Example Question #62 : Geometry

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An acute Isosceles triangle has two sides with length  and one side length . The length of side   inches. If the length of , what is the perimeter of the triangle?

Possible Answers:

 inches

 inches

 feet

 feet

 inches

Correct answer:

 inches

Explanation:

In order to solve this problem, first find the length of the missing sides. Then apply the formula: 

The missing side equals:





Then, apply the perimeter formula by plugging in the side values: 

Example Question #63 : Geometry

An acute Isosceles triangle has two sides with length  and one side length . The length of side   ft. If the length of   , what is the perimeter of the triangle? 

Possible Answers:

 foot

 foot

 foot

 inches

 inches 

Correct answer:

 inches 

Explanation:

To solve this problem apply the formula: .

However, first calculate the length of the missing side by:

 , Note that 




Since, it takes  inches to make one foot, the perimeter is equal to  inches. 

Example Question #64 : Geometry

An acute Isosceles triangle has two sides with length  and one side length . The length of side   inches. The length of side  . Find the perimeter of the triangle.

Possible Answers:

 inches

 inches

 inches

 inches

 inches

Correct answer:

 inches

Explanation:

To find the perimeter of this triangle, apply the formula: 









Note: Since this is an acute Isosceles triangle, the length of the base must be smaller than the length of both of the equivalent sides. 

Example Question #11 : Isosceles Triangles

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The obtuse Isosceles triangle shown above has two sides with length  and one side length . The length of side   inches. Side length . Find the perimeter of the triangle. 

Possible Answers:

 inches

 inches

 inches

 inches

 inches

Correct answer:

 inches

Explanation:

To find the perimeter of this triangle, apply the perimeter formula:



Since, , and  then  must have a value of: 

This triangle has two side lengths of  inches, and one side length of  inches. 

Thus, the solution is:

Example Question #1251 : Gre Quantitative Reasoning

A triangle has two sides with length  and one side length . The length of side   yard. If the length of   the length of side , what is the perimeter of the triangle? 

Possible Answers:

 yard

 yard

 yard

 yard

 yard

Correct answer:

 yard

Explanation:

The first step to solving this problem is that we must find the length of length  Since,  is 4 the length of side , use the following steps: 




Now, apply the formula: 




Example Question #11 : Triangles

An isosceles triangle has an angle of 110°.  Which of the following angles could also be in the triangle?

Possible Answers:

110

20

35

55

90

Correct answer:

35

Explanation:

An isosceles triangle always has two equal angles. As there cannot be another 110° (the triangle cannot have over 180° total), the other two angles must equal eachother. 180° - 110° = 70°. 70° represents the other two angles, so it needs to be divided in 2 to get the answer of 35°. 

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