Is there a triangle with 3 acute angles?

Answer 1

Yes. An equilateral triangle has 3 equal sides and as such, has 3 angles that are less than 90 degrees, or acute angles. Also, an isosceles triangle which has at least 2 equal sides can have a third side that is shorter than the two equal sides, creating a triangle with 3 acute angles. However, if the third side is made longer than the 2 equal sides, one angle becomes greater than 90 degrees, or obtuse. So, all equilateral triangles are have 3 acute angles, but only some isosceles triangles have 3 acute angles, those having one side shorter than the two equal sides.