One angle of an isosceles triangle measures 80°. Which other angles could be in that isosceles triangle?

Question

Its a triangle

Answer 1

There is more than one answer. An isosceles triangle has two equal angles and two matching sides (if the third side and angle also match, it becomes "equilateral" and "equiangular" instead). If we assumed that the 80° is one of the equal angles, then there is another 80° angle. That makes 160°. Since a triangle always totals 180°, you simply subtract:

180° - 160° = 20°

But what if we were wrong? What if the 80° was the only different angle instead? In that case, the two remaining angles total:

180° - 80° = 100°               Since we have two identical angles remaining, we need only divide the 100° in half to get the final answer:

100° / 2 = 50°

And there you have it! Your possible triangles are:

20°,80°,80°     and 50°,50°,80°