You can put this solution on YOUR website! Think this through logically. The sum of the interior angles of a triangle must be 180 degrees. Acute angle is less than 90 degrees. Any two angles of a triangle must have sum of less than 180 degrees. You require two equal angles for any isosceles triangle. The sum of these two must be less than 180 degrees so any one of these two angles must be less than 90 degrees, meaning "acute".
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