Sally is having a problem with her puppy leaving the yard so she decides to build a new fence. the length of the yard is 10 feet more than 3 timesthe width. she needs 60 feet of fencing to do the job. find the length of the yard

1. You have that the length of the yard is 10 feet more than 3 times the width. Then, you can write the following expression:

Where is the length and is the width.

2. She needs 60 feet of fencing, which is the perimeter.

3. The formula of the perimeter of a rectangle is:

4. Therefore, you can substitute the first expression of the lenght into the formula of the perimeter and solve for the width:

5. Now you can calculate the length:

The answer is: The length of the yard is 25 feet.