Question

Determine if the statement is always, sometimes, or never true:

An equilateral triangle is an acute triangle.

always
sometimes
never

Answer 1

A couple notions will help you answer this question.
1. Knowing the sum of all three angles in a triangle.
2. Knowing that an equilateral triangle is equiangular, and what that implies about how big each angle is.
3. Knowing what an acute triangle is.

Answer 2

Always. Isosceles triangle has at least two sides of equal length. Equilateral triangle has three sides of equal length.

So an equilateral triangle is always an isosceles triangle.

The isosceles triangle is, however, sometimes an equilateral triangle.

Answer 3

^ Interesting comments there, @nitz . I don't know how it's relevant here, and what you said also depends on how you define 'isosceles.'