GMAT Math : Geometry

Study concepts, example questions & explanations for GMAT Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #321 : Geometry

Calculate the perimeter of an equilateral triangle whose side length is .

Possible Answers:

Correct answer:

Explanation:

The perimeter of an equilateral triangle is:

Thus.

Example Question #322 : Geometry

Find the perimeter of an equilateral triangle whose side length is .

Possible Answers:

Correct answer:

Explanation:

To find the perimeter, you must multiply the side length by . Thus,

Example Question #323 : Geometry

Calculate the perimeter of an equilateral triangle whose side length is .

Possible Answers:

Correct answer:

Explanation:

To solve, simply multiply the side length by . Thus,

Example Question #1 : Calculating The Perimeter Of An Acute / Obtuse Triangle

A triangle has 2 sides length 5 and 12.  Which of the following could be the perimeter of the triangle?

I. 20

II. 25

III. 30

Possible Answers:

II and III only.

I only

All 3 are possible.

I and II only

III only

Correct answer:

II and III only.

Explanation:

For a triangle, the sum of the two shortest sides must be greater than that of the longest.  We are given two sides as 5 and 12.  Our third side must be greater than 7, since if it were smaller than that we would have  where is the unknown side.  It must also be smaller than 17 since were it larger, we would have .

 

Thus our perimeter will be between and . Only II and III are in this range.

Example Question #2 : Calculating The Perimeter Of An Acute / Obtuse Triangle

Export-png__6_

Triangle  has sides . What is the perimeter of triangle ?

Possible Answers:

Correct answer:

Explanation:

To calculate the perimeter, we simply need to add the three sides of the triangle.

Therefore, the perimeter is , which is the final answer.

Example Question #3 : Calculating The Perimeter Of An Acute / Obtuse Triangle

Export-png__7_

Triangle  has height . If  is the midpoint of  and , what is the perimeter of triangle ?

Possible Answers:

Correct answer:

Explanation:

Since BD is the height of triangle ABC, we can apply the Pythagorean Theorem to, let's say, triangle DBC and .

Since the basis of the height is at the midpoint of AC, it follows that triangle ABC, is an isoceles triangle.

We can find the perimeter by multiplying BC by 2 and add the basis of the triangle AC, which has length of .

The final answer is therefore .

Example Question #1 : Acute / Obtuse Triangles

An acute triangle has side lengths of , and . What is the perimeter of the triangle?

Possible Answers:

Correct answer:

Explanation:

For any given triangle, the perimeter  is the sum of the lengths of its sides. Given side lengths of , and 

Example Question #4 : Calculating The Perimeter Of An Acute / Obtuse Triangle

An acute triangle has side lengths of , and . What is the perimeter of the triangle?

Possible Answers:

Correct answer:

Explanation:

For any given triangle, the perimeter  is the sum of the lengths of its sides. Given side lengths of , and 

Example Question #3 : Acute / Obtuse Triangles

An acute triangle has side lengths of , and . What is the perimeter of the triangle?

Possible Answers:

Correct answer:

Explanation:

For any given triangle, the perimeter  is the sum of the lengths of its sides. Given side lengths of , and 

Example Question #1 : Acute / Obtuse Triangles

Is it true that  ?

Suppose you want to answer this question, and you know that  and . Which of the following additional facts would help you to answer this question one way or the other?

Possible Answers:

None of these statements would be sufficient to answer the question.

Correct answer:

Explanation:

If you know either that  or , you have three congruencies - two sides and a nonincluded angle. This is not enough to establish triangle congruence,

If you know that , this, along with the other two statements, establishes that ; all this proves is that both triangles are isosceles.

If you also know that , however, the three statements together make three side congruencies, setting up the Side-Side-Side criterion for triangle congruence.

Tired of practice problems?

Try live online GMAT prep today.

1-on-1 Tutoring
Live Online Class
1-on-1 + Class
Learning Tools by Varsity Tutors