Q: Is it true that isosceles triangles have to have acute angles?

Write your answer...

Submit

Still have questions?

Continue Learning about Math & Arithmetic

Yes, it is true that an isosceles triangle can be acute or obtuse. As long as a triangle has two equal angles and two equal sides, it is isosceles. That situation can occur in both acute (all angles less than 900) and obtuse (one angle more than 900) triangles. Examples are a triangle with the angles being 75-75-30 degrees (acute) and one having angles of 120-30-30 (obtuse). Of course the sides of the angles that are equal would also be equal, so both examples are of isosceles triangles.

No, it is not true.

All acute triangles have 3 interior angles and 3 exterior angles. This is true for all triangles.

Not true. A triangle with angles of 90, 45 and 45 is a right angled isosceles triangle. If you take a square piece of paper and fold it in half - from corner to corner - you will get this shape.

False. Equilateral triangles are equilateral. All isosceles triangles have two of the sides the same, with the hypotenuse being longer than the other two.

Related questions

The two acute angles are always equal.

Yes, it is true that an isosceles triangle can be acute or obtuse. As long as a triangle has two equal angles and two equal sides, it is isosceles. That situation can occur in both acute (all angles less than 900) and obtuse (one angle more than 900) triangles. Examples are a triangle with the angles being 75-75-30 degrees (acute) and one having angles of 120-30-30 (obtuse). Of course the sides of the angles that are equal would also be equal, so both examples are of isosceles triangles.

true

No, it is not true.

All acute triangles have 3 interior angles and 3 exterior angles. This is true for all triangles.

the answer is true, apex

Not true. A triangle with angles of 90, 45 and 45 is a right angled isosceles triangle. If you take a square piece of paper and fold it in half - from corner to corner - you will get this shape.

They can be any size. The only unchanging 'fact' which is true about all isosceles triangles is that two of them are equal.

True

All isosceles triangles are not equilateral triangles

No

True