Perimeter of an Isosceles Triangle
The perimeter of an isosceles triangle is obtained as the addition of the three sides of the triangle. Having two equal sides, the perimeter is twice the repeated side (a) plus the different side (b).

In an isosceles triangle, if the repeating side (a) and the angle they form are known, the other side (b) should be found by Law of Cosines (Cosine Rule).

Download this calculator to get the results of the formulas on this page. Choose the initial data and enter it in the upper left box. For results, press ENTER.
Triangle-total.rar or Triangle-total.exe
Note. Courtesy of the author: José María Pareja Marcano. Chemist. Seville, Spain.
Exercise
Being an isosceles triangle with two equal sides, a=3 cm and a different side of b=2 cm.
What is its perimeter?
To calculate this perimeter we add the repeated side multiplied by two plus the unequal side, i.e.:

It is obtained that the isosceles triangle’s perimeter is 8 cm.
AUTHOR: Bernat Requena Serra
YEAR: 2018
as soon as I detected this web site I went on reddit to share some of the love with them.
A common error is to assume that a triangle that has a fixed perimeter must also have a fixed area. This is definitely
Right
Evidently