Is an isosceles triangle always, sometimes or never a right triangle?

1 Answer
Nov 14, 2015

Sometimes, if it is a 45-45-90 triangle.


To be a right triangle, one of the angles has to be 90 degrees. This means that the two remaining angles have to be 90 degrees when summed up. (Because 90 + 90 = 180, which is the sum of all the angles in any triangle).

Since we are talking about an isosceles triangle, we know that two of the angles have to be the same. That means that 2 similar angles added up will be 90 degrees. Let's call the angles x:

#2x = 90#
#x = 45#

That means that we can only have a right triangle, that also is a isosceles triangle, when the degrees are 45, 45 and 90.