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.
No
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.
An obtuse triangle must have two acute angles and these can be congruent.
Not at all.
true
No, it is not true.
No
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.
I assume that the second use of the word "triangle" in the question should be angle. An obtuse triangle must have two acute angles.
An obtuse triangle must have two acute angles and these can be congruent.
Not at all.
An obtuse triangle has 1 obtuse angle and 2 acute angles which add up to 180 degrees.
An obtuse triangle or a right angle triangle. An equilateral is definitely an isoceles triangle * * * * * Not true. An obtuse or right angled triangles can be isosceles. It depends on the sizes of the two smaller angles. An isosceles triangle has two equal angles so a triangle with angles of size [A, (180-A)/2, (180-A)/2] degrees where 90 < A < 180 degrees would be an obtuse angled isosceles triangle. A triangle with angles of size (90, 45, 45) degrees is a right angled isosceles triangle.
This is a true statement that defines a triangle in geometry. However, there are many different types of triangles, such as obtuse, acute, scalene, right, equilateral, and isosceles triangles.
True
The two acute angles are always equal.