3D-Printing Club: Signs and Reflections

Use coordinate signs to check part layouts on a print bed.

Read the Layout

The club uses a top view of the print bed. The origin is its center, and coordinates are in centimeters. Use Roman numerals I, II, III, and IV for quadrants.

The labeled points mark the centers of four parts. Match each point to its quadrant.

A new part must have a negative x-coordinate and a positive y-coordinate. Where should its center be placed?

A. In Quadrant IV.B. In Quadrant III.C. In Quadrant II.D. In Quadrant I.

A support post has its center at (−3, 0). How should the club describe its location?

A. It lies on the x-axis, not in a quadrant.B. It lies in Quadrant II, above the x-axis.C. It lies on the y-axis, not in a quadrant.D. It lies in Quadrant III, below the x-axis.

The club reflects part B across the x-axis. Use the signs of the reflected point's coordinates to identify its quadrant.

The reflected point is in Quadrant .

Check Mirrored Features

Use the grid to compare the four holes in a model's base plate.

Which reflection maps hole P onto hole Q?

A. Reflect across the x-axis only.B. Reflect across both axes in sequence.C. Reflect across neither axis.D. Reflect across the y-axis only.

Hole P is at (−3, 2). Reflect it across the x-axis. Write the reflected coordinates.

(, )

Starting at Q, change the signs of both coordinates. Which hole is at the resulting point?

A. Hole P.B. Hole R.C. Hole S.D. Hole Q.

A hole was reflected across the y-axis, and its image is R at (−3, −2). What were the original hole's coordinates?

(, )

A design tool reflects any point across the x-axis. Which rule correctly describes the coordinates of its image?

A. Keep x unchanged and replace y with its opposite.B. Replace x with its opposite and keep y unchanged.C. Replace both x and y with their opposites.D. Exchange x and y without changing their signs.

Review New Designs

Apply the reflection rules to each new part. Sketch on scrap paper if needed.

10.

Mina places a fastening hole at (5, −4). A matching hole must be its reflection across the x-axis. Write the matching hole's coordinates.

(, )

11.

A model's left tab has its center in Quadrant II. Andre reflects that center across the y-axis to place a right tab. Which signs must the right tab's coordinates have?

A. Its x-coordinate is negative; its y-coordinate is negative.B. Its x-coordinate is negative; its y-coordinate is positive.C. Its x-coordinate is positive; its y-coordinate is positive.D. Its x-coordinate is positive; its y-coordinate is negative.

12.

A corner of a phone stand's base is at (−4, −1). The club reflects it across the x-axis, then reflects the result across the y-axis. Write the final coordinates.

(, )

13.

A model's center notch is at (0, −5). The design tool reflects it across the y-axis. What happens to the notch's location?

A. It moves to (0, 5).B. It stays at (0, −5).C. It moves to (5, 0).D. It moves to (−5, 0).

14.

Jalen reflects a detail at (−2, 5) across the y-axis and records (−2, −5). Explain his mistake. Give the correct coordinates and quadrant of the reflected detail.