Choose the word which is different from the rest.

The answer is D. Triangle.

A rectangle, square, and cube are all shapes with three dimensions. A triangle is a shape with two dimensions.

A rectangle is a four-sided shape with four right angles. A square is a rectangle with all four sides of equal length. A cube is a three-dimensional shape with six square faces. A triangle is a three-sided shape with three angles.

The only shape that is different from the rest is the triangle. The other three shapes have three dimensions, while the triangle has two dimensions.