A pantograph is a four-bar linkage mechanism used for drawing. It consists of two long bars and two short bars pivoted to one another so that they can move freely in the plane. In the version shown in Figure 3 below the short bars are half the lengths of the long ones.The point O is held fixed. There is a pointer at X and a pencil at Y. As the pointer at X is traced over a shape, the pencil at Y draws the shape enlarged by a factor of two.In Figure 3 if O and Q are both held fixed, the point Y.

Correct answer: C. can move in a straight line

A. cannot move
B. can move on a circular path
C. can move in a straight line
D. can move freely

Explanation

The pantograph's structure as a four-bar linkage means that when points O and Q are fixed, the movement of point Y is constrained. The linkage creates a situation where Y can only move along a straight path, defined by the geometric configuration and constraints of the linkage. Option A is incorrect because Y can still move, albeit in a restricted manner. Option B is incorrect because the movement is not circular. Option D is incorrect because the movement is not unrestricted; it is specifically linear due to the fixed points.

Last updated 3 September 2026

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