### All GMAT Math Resources

## Example Questions

### Example Question #17 : Equilateral Triangles

The area of an equilateral triangle is . What is the perimeter of ?

**Possible Answers:**

**Correct answer:**

The area is given, which will allow us to calculate the side of the triangle and hence we can also find the perimeter.

The area for an equilateral triangle is given by the formula

, where is the length of the side of the triangle.

Therefore, , where is the area.

Thus , and the perimeter of an equilateral triangle is three times the side, hence, the final answer is .

### Example Question #18 : Equilateral Triangles

A given equilateral triangle has a side length of . What is the perimeter of the triangle?

**Possible Answers:**

Not enough information provided.

**Correct answer:**

An equilateral triangle with a side length has a perimeter .

Given:

,

.

### Example Question #19 : Equilateral Triangles

A given equilateral triangle has a side length of . What is the perimeter of the triangle?

**Possible Answers:**

**Correct answer:**

An equilateral triangle with a side length has a perimeter .

Given:

,

.

### Example Question #20 : Equilateral Triangles

A given equilateral triangle has a side length of . What is the perimeter of the triangle?

**Possible Answers:**

Not enough information provided.

**Correct answer:**

An equilateral triangle with a side length has a perimeter .

Given:

,

.

### Example Question #21 : Equilateral Triangles

Given the following regarding Triangle .

I)

II) Side is equal to light-years

What is the length of side ?

**Possible Answers:**

light years

light years

light years

light years

light years

**Correct answer:**

light years

The trick to this one is to carefully put together what you are given.

We know that two of our angles are equal to 60 degrees. This means that the last angle is also 60 degrees. This make HFT an equilateral triangle.

Equilateral triangles always have equal sides and equal angles, so our last side has to be 7 light years as well.

### Example Question #22 : Equilateral Triangles

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

**Possible Answers:**

**Correct answer:**

The perimeter of an equilateral triangle is:

Thus.

### Example Question #23 : Equilateral Triangles

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

**Possible Answers:**

**Correct answer:**

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

### Example Question #24 : Equilateral Triangles

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

**Possible Answers:**

**Correct answer:**

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