The correct answer is:
True.
Explanation:
An isosceles triangle is one that has two sides and two angles congruent.
The angles can both be acute; for example, we could have an isosceles triangle in which the base angles are 80°. This makes 80+80 = 160°. A triangle has 180° total; this leaves 180-160 = 20°. This means all 3 angles are acute, so the triangle is an acute triangle.
In order to have an obtuse triangle, only one angle must be obtuse. Imagine one angle is 100°. This leaves 180-100 = 80° for the other two. To make it isosceles, they could both be equal: 80/2 = 40° each. This makes it an obtuse triangle.
