# ISEE Lower Level Math : How to find the perimeter of a triangle

## Example Questions

### Example Question #41 : How To Find The Perimeter Of A Triangle

Use the following triangle to answer the question:

Find the perimeter.

Explanation:

To find the perimeter of a triangle, we will use the following formula:

where a, b, and c are the lengths of the sides of the triangle.

Now, let's look at the triangle.

We can see it has sides with lengths of 11cm, 6cm, and 12cm.

Knowing this, we can substitute into the formula.  We get

### Example Question #42 : How To Find The Perimeter Of A Triangle

Find the perimeter of an equilateral triangle with a base of 6in.

Explanation:

To find the perimeter of a triangle, we will use the following formula:

where a, b, and c are the lengths of the sides of the triangle.

Now, we know the base of the triangle is 6in.  Because it is an equilateral triangle, we know that all sides are equal.  Therefore, all sides are 6in.

Knowing this, we can substitute into the formula.  We get

### Example Question #43 : How To Find The Perimeter Of A Triangle

Use the following triangle to answer the question:

Find the perimeter.

Explanation:

To find the perimeter of a triangle, we will use the following formula:

where a, b, and c are the lengths of the sides of the triangle.

Now, given the triangle

we can see it has sides of length 8cm, 4cm, and 6cm.

Knowing this, we can substitute into the formula.  We get

### Example Question #44 : How To Find The Perimeter Of A Triangle

Find the perimeter of an equilateral triangle with a base of 5in.

Explanation:

To find the perimeter of a triangle, we will use the following formula:

where a, b, and c are the lengths of the sides of the triangle.

Now, we know the base of the triangle is 5in.  Because it is an equilateral triangle, we know that all sides are equal.  Therefore, all sides are 5in.

Knowing this, we can substitute into the formula.  We get

### Example Question #45 : How To Find The Perimeter Of A Triangle

An isosceles triangle measures  inches along its two equal sides, and  inches along its third side. What is the perimeter of the triangle?

Explanation:

To find the perimeter of any object, simply add the length of each side together.  For the triangle above, add the equal side twice (there are two of them). The best answer is:

### Example Question #46 : How To Find The Perimeter Of A Triangle

An isosceles triangle measures  inches along its two equal sides, and  inches along its third side. What is the perimeter of the triangle?

Explanation:

To find the perimeter of any object, simply add the length of each side together. The best answer is:

inches

### Example Question #47 : How To Find The Perimeter Of A Triangle

An equilateral triangle measures  inches along its three equal sides.  What is the perimeter of the triangle?

Explanation:

To find the perimeter of any object, simply add the length of each side together.  In the case of an equilateral triangle, because all three sides are equal, and there are three of them, you can also multiply the side length by three.  The best answer is:

inches

### Example Question #48 : How To Find The Perimeter Of A Triangle

An equilateral triangle measures  inches along its three equal sides.  What is the perimeter of the triangle?

Explanation:

To find the perimeter of any object, simply add the length of each side together.  In the case of an equilateral triangle, because all three sides are equal, and there are three of them, you can also multiply the side length by three.  The best answer is:

inches

### Example Question #49 : How To Find The Perimeter Of A Triangle

Find the perimeter of an equilateral triangle with a base of 18in.

Explanation:

To find the perimeter of a triangle, we will use the following formula:

where a, b, and c are the lengths of the sides of the triangle.

Now, we know the base of the triangle has a length of 18in.  Because it is an equilateral triangle, all lengths are the same.  Therefore, all lengths are 18in.

Knowing this, we can substitute into the formula.  We get

### Example Question #50 : How To Find The Perimeter Of A Triangle

Find the perimeter of an equilateral triangle with a base of 14in.