Question

The perimeter of an isosceles triangle is 168mm.The base is 18mm more than each of the legs. what is the length of the longest side.
Please can someone explain this to me

Answer 1

Answer:

The length of the longest side is 68mm

Step-by-step explanation:

The perimeter of a triangle is equals to the sum of all its sides

P=a+b+c

The triangle is isosceles, so two of its sides are equal, have the same length.

So: a=b, then

P=2a+c=168mm

Moreover, we know that the base is 18mm more than each of the legs, this means: c=18mm+a, where we obtain that a=c-18mm.

So, the system of equations is solved, lets use the above result in Perimeter`s equation.

168mm=2*(c-18mm)+C

From here we have:

168mm=3c-36mm

We obtain the following result: c= 68mm, this the length of the longest side