One Move, Then Another

Part of the Transformations & Constructions section of Coddy's Geometry journey. Lesson 16 of 61.

Moves can be done one after another. The second move acts on the image of the first, so work in order: find where the first move sends each corner, then move those points again.

$Triangle PQR slid by 3, 1, then reflected in the x-axis$

Here PQR is first translated by ⟨3, 1⟩, then reflected in the x-axis. P(1, 2) slides to (4, 3), shown faintly. The reflection then sends (4, 3) to (4, -3), so P' is (4, -3). Q and R go through the same two steps. Only the last position is the image; the middle one is a stop on the way.

Challenge

Triangle ABC is translated by ⟨2, -4⟩ and then reflected in the y-axis (x = 0). Draw the final image: drag A', B' and C' into place, then press Check.

Try it yourself

$Move the shape onto its target$

Move the shape onto its target

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Transformations & Constructions

1Translations

Sliding a Shape Draw the Image Image Coordinates The Translation Rule Recap: Translations

4Combining Moves

One Move, Then AnotherOrder Matters Two Mirrors Name the Move Recap: Combining Moves

7Drawing on Squared Paper

Lengths by Pythagoras Perpendicular Steps Squares by Area Right Triangles by Area Midpoints on the Grid Recap: Squared Paper

10Perpendiculars and Parallels

Perpendicular From a Point Perpendicular at a Point Parallel Through a Point Tools You Have Earned Recap: Parallels