Unit 10A

Transformations

1. The triangle ABC has vertices A(2,1), B(4,1) and C(4,2).

Draw, on the diagram below, the image of the triangle ABC under

(a) an anticlockwise rotation of 90 about the origin O, labelling the image X,

(b) a reflection in the line y=-x, labelling the image Y.

x y -5 -4 -3 -2 -1 0 1 2 3 4 5 4 3 2 1 -1 -2 -3 -4 A B C

2. Answer the whole of this question on a sheet of graph paper.

The triangle ABC has vertices A(2,0), B(4,4) and C(0,1). The triangle PQR has vertices P(8,-2), Q(4,0) and R(7,-4). The triangle LMN has vertices L(-2,-7), M(-6,-9) and N(-3,-5). Draw these triangles on graph paper, using a scale of 1 cm to 1 unit on each axis, and label the vertices. ΔABC can be mapped onto ΔPQR by an anti-clockwise rotation about the origin followed by a translation.

(a) State the angle of rotation.

(b) Find the matrix which represents this rotation.

(c) Find the column vector of the translation.

(d) Given that ΔABC can be mapped onto ΔPQR by a single rotation, find the coordinates of the centre of this rotation.

(e) Given that ΔABC can be mapped onto ΔLMN by a translation of (0-3) followed by a reflection in the mirror line m, draw the line m on your graph and label it clearly.

(f) Find the equation of m.

3. (a) Describe completely a single transformation which maps ΔABC onto ΔDEF.

(b) Describe completely a single transformation which maps ΔABC onto ΔPQR.

x y 0 1 2 3 4 5 6 7 8 -1 -2 -3 -4 -5 -6 1 2 3 -1 -2 -3 A B C D E F P Q R

4. The whole of this question should be answered on graph paper.

(a) Using a scale of 1 cm to represent 1 unit on each axis, draw x and y axes, taking values of x from -8 to 12 and values of y from -6 to 14. Draw and label the triangle X, with vertices (2,4), (4,4) and (4,1).

(b) The single transformation U maps the triangle X onto the triangle U(X) which has vertices (6,12), (12,12) and (12,3).

Draw and label the triangle U(X) and describe fully the transformation U.

(c) The transformation R is a clockwise rotation of 90 about the origin. Draw and label the triangle R(X).