Transformations and combining them
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Grades 4–6The first question is what today's lesson needs. The others bring back earlier topics.
- A1Needed today[1 mark]
Find the midpoint of and .
Answer - A2Last lesson[1 mark]
Two triangles have two sides and the angle between them equal. Which condition shows they are congruent?
Answer - A3From chapter 5[1 mark]
£500 grows by a year for 2 years, compounded. Find the final amount.
Answer - A4Key Stage 3[1 mark]
Work out .
Answer
Example, then your turn
Grades 4–7Your teacher works through each example with you. Then try the one beside it.
Rotate the triangle clockwise about .
- B1[2 marks]
Rotate the triangle anticlockwise about . Give the new vertices.
Answer
Enlarge the triangle by scale factor , centre .
- B2[2 marks]
Enlarge the triangle by scale factor , centre . Give the new vertices.
Answer
Practice
Grades 5–7- C1[2 marks]
Shape has rotational symmetry of order . Work out the smallest turn that maps onto itself. Shape first fits onto itself after . Give its order.
Answer order - C2[2 marks]
A translation maps onto . Write down its column vector. The same translation maps onto . Find .
Answervector
- C3[3 marks]
Reflect triangle in the line . Give the vertices of the image. Which vertex of is invariant? Why?
Answer ; invariant - C4[3 marks]
Enlarge triangle by scale factor , centre . Write down the coordinates of the vertices of the image.
Answer
Exam-style questions
Grades 6–8- D1
Triangle is shown on the grid.
(a)[2 marks]Rotate triangle clockwise about . Label the image . Write down the coordinates of the vertices of .
Answer(b)[2 marks]Reflect triangle in the -axis. Label the image . Write down the coordinates of the vertices of .
Answer(c)[2 marks]Describe fully the single transformation that maps triangle onto triangle .
AnswerTotal for D1: 6 marks
- D2
Sam says, "Triangle is an enlargement of triangle with scale factor ."
Triangles and are shown on a grid of centimetre squares.
(a)[2 marks]Explain why Sam is wrong, and say which enlargement does have scale factor .
(b)[3 marks]Describe fully the single transformation that maps triangle onto triangle .
Answer(c)[2 marks]Triangle is enlarged by scale factor , centre , to give triangle . Work out the area of triangle .
AnswerTotal for D2: 7 marks
Extension
Grade 8 and beyondNo route is given. The hints are at the end of the sheet. Use one at a time.
- E1[4 marks]
A rotation of clockwise maps the point onto . Find the coordinates of the centre of the rotation. Then find the image of under the same rotation.
Hint 1 · What to try
The centre is the same distance from as from , and the turn about it is a quarter turn.
Hint 2 · The first line
Call the centre . The step from the centre to is . A quarter turn clockwise makes a step into .
Hint 3 · The full method
So . That gives and .
Answercentre image
How did it go?
Colour one circle on each line.| Not yet | Nearly | Yes | |
|---|---|---|---|
| I can rotate, reflect, translate and enlarge a shape, and describe each one fully. | |||
| I can enlarge by a fractional or a negative scale factor from any centre. | |||
| I can replace two transformations by one, and find invariant points. |
Answers and mark scheme
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