Name the Move
Part of the Transformations & Constructions section of Coddy's Geometry journey. Lesson 19 of 61.
Given a shape and its image after a single move, you can name the move by asking three questions in order.
Is it the same size? If not, it is a dilation. Is it flipped? Read the corners round the shape and round the image; if one goes clockwise and the other counterclockwise, it is a reflection. Does it face the same way? Then it is a translation. Otherwise it has turned: a rotation.
In the figure the image is the same size. P, Q, R run counterclockwise, but P', Q', R' run clockwise, so it is flipped: a reflection. P(1, 1) and P'(1, -3) are one above the other, so the mirror is level and halfway between them: y = -1.
Challenge
Triangle ABC has been moved onto the dashed target in one move. Which move is it? Pick it, then press Check.
Try it yourself
Move the shape onto its target
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Transformations & Constructions
7Drawing on Squared Paper
Lengths by PythagorasPerpendicular StepsSquares by AreaRight Triangles by AreaMidpoints on the GridRecap: Squared Paper10Perpendiculars and Parallels
Perpendicular From a PointPerpendicular at a PointParallel Through a PointTools You Have EarnedRecap: Parallels5Dilations
Scaling From a CenterShrinking a ShapeDilating About a PointNegative Scale FactorsRecap: Dilations8Compass and Straightedge
Circles Keep DistancesWhy the Sides MatchAngles You BuiltA 60° AngleRecap: Equilateral Triangle