How do you determine the value of isosceles triangles?

There's really no such thing as the value of a triangle. 

Every triangle has three sides, three angles, a base, a height, and an area,
and there could be problems that ask us to find any one of those. 

Whatever we need to find, the process is always the same: 

-- Take the information that's given.

-- Gather up everything you can remember that talks about a relationship
between what you're given and what you need to find.

-- Use them together to find the missing value.