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

where a is the length of one side. An equilateral triangle has 3 equal sides, so we can use any side in the formula. To find the length of one side, we will solve for a. Now, we know the perimeter of the triangle is 42cm. So, we will substitute and solve for a. We get

Therefore, the length of one side of the equilateral triangle is 14cm.

The three sides of the triangle are known.  Add all the sides together.

The answer is:  

There are three sides in a triangle.

To determine the length of a side, multiply the quantity by one-third.

The answer is:  

The formula to find the perimeter of an equilateral triangle is

where a is the length of one side of the triangle. Because it is an equilateral triangle, all sides are equal. Therefore, we can use any side in the formula. To find the length of one side, we will solve for a.

Now, we know the perimeter of the triangle is 45in. So, we can substitute and solve for a. So, we get

Therefore, the length of one side of the equilateral triangle is 15in.

The formula to find the perimeter of an equilateral triangle is

where a is the length of one side of the triangle. An equilateral triangle has 3 equal sides, so we can use any side in the formula. To find the length of one side, we will solve for a.

Now, we know the perimeter of the triangle is 123in. So, we will substitute and solve for a. We get

Therefore, the length of one side of the equilateral triangle is 41in.

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 lengths of 9in, 3in, and 10in. Knowing this, we can substitute into the formula. We get

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.

So, given the following triangle

we can see it has sides of length 8cm, 4cm, and 6cm. So, we can substitute. We get

The triangle is not specified whether if it is an isosceles, right triangle, or equilateral triangle.  

We only can conclude that there's only one known side.  There is insufficient information to find the total perimeter of the triangle.

The answer is:  

The perimeter of an equilateral triangle is three times the given side length, since all three sides are congruent.

Multiply the known side by three.

Simplify the inner terms.

The answer is:  

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 with lengths of 10ft, 6ft, and 12ft. So, we can substitute. We get