Question

pentagon
quadrilateral (rectangle)
triangle (right)
triangle (acute)
quadrilateral (square)
be identified as a

Explanation:

A triangle has three sides. The given shape has three sides and one right - angle. A pentagon has five sides, a rectangle and square are quadrilaterals (four - sided shapes). An acute triangle has all angles less than 90 degrees. This shape has a 90 - degree angle.

Answer:

Triangle (Right)