5 A rectangle is 4 cm long and 3 cm wide. It is enlarged by scale factor 3. a Work out i the perimeter of the original rectangle ii the perimeter of the enlarged rectangle. b Find the missing number. Enlarged perimeter = original perimeter × u 3 cm Q5 Strategy hint Sketch the rectangle. Mark on the lengths after the enlargement. 4 cm Q6 hint 6 a For the rectangle in Q5 work out i the area of the original rectangle ii the area of the enlarged rectangle. b Find the missing number. Enlarged area= original area × u Use your sketch and measurements from Q5a. 7 A cuboid is enlarged by scale factor 2. a Work out i the volume of the original cuboid ii the volume of the enlarged cuboid. b Find the missing number. Enlarged volume = original volume × u 4 cm 2 cm A 2 cm 4 cm 5 cm 10 cm Q1 hint Planes of symmetry The two pieces must be reflections of each other about the plane of symmetry. 1 The diagrams show a cuboid divided by four planes. Which diagram does not show a plane of symmetry? A B C D 2 In this triangular prism the cross-section is an isosceles triangle. How many planes of symmetry does the prism have? Q2 hint How many ways could you cut it in half? Would each half be a reflection of the other? Enrichment 1 Draw a grid with x- and y-axes from −10 to 10. a Plot the point (3, 4). b Reflect the point in the x-axis. c What are the coordinates of the new point? d Copy and complete the table. Point (3, 4) (2, 7) (1, 5) (9, 2) (−1, 3) (2, −4) (−2, −7) (−8, −1) (0, 3) Reflection in the x-axis 2 Reflect In these lessons you have answered questions about reflection rotation translation enlargement Write a definition for each of them, using one of these descriptions: flips over changes size changes position turns around For each definition, draw a sketch to show what the definition means. How did your definition help you choose the shapes? Reflect e Is there a way of working out the reflection without plotting the points? f Repeat for reflecting points in the y-axis. Unit 5 Transformations 122