13.
the perimeter of an isosceles triangle is 14. if the
length of the base of the triangle is one less than
the length of each leg, find the length of a leg.

5 units

Step-by-step explanation:

An isosceles triangle is a triangle with two legs that have the same length. The perimeter of a triangle is the sum of the lengths of all sides of the triangle. Now taking this into account, we know that:

2L + B = 14 units

Where:

L is the measure of one leg

B is the measure of the base

Since two legs are the same and the base is 1 less, this means the measure of each leg would be:

B = L -1

Now we have two equations:

2L + B = 14 units

B = L- 1

We plug one equation into the other and make 1 equation:

2L + (L-1) = 14 units

Get rid of the parentheses:

2L + L - 1 = 14

Combine like terms:

3L - 1 = 14

Add 1 to both sides of the equation:

3L - 1 + 1 = 14 + 1

3L = 15

Divide both sides by 3:

3L/3 = 15/3

L = 5

So the length of a leg is 5 units

Let's check!

B = L - 1

B = 5 - 1

B = 4

Then we use that to solve for the perimeter:

2L + B

2(5) + 4

10 + 4 = 14