Enlarging animals

Enlarging animals

Pencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about working out scale factors and lengths of sides.
Petra was making a collage of animal pictures.
She used the photocopier to enlarge some pictures she found online.
For each picture find:
 
1)  the scale factor of the enlargement, and
2)  the length of the marked side.

Question 1Change answer

 diagram of enlargement
[Not drawn to scale]
a)  i)  scale factor = 
     ii) side x =  mm
 

Question 1Change answer

diagram of enlargement
[Not drawn to scale]
b)  i)   scale factor = 
     ii)  side y =  mm
 

Question 1Change answer

diagram of enlargement
[Not drawn to scale]
c)  i)   scale factor = 
     ii)  side z =  mm
Task administration: 
This task can be completed with pen and paper or online (with NO auto marking).
Level:
5
Curriculum info: 
Maths, Geometry and Measurement, Transformation
Keywords: 
enlargement, resizing, scale factor, length
Description of task: 
From three different sized animal pictures and their enlargements, students are required to identify the scale factor and the length of an unknown side.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Geometric thinking, set 6
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 

 

Y11 (10/2001)

a)

i)
ii)

3
90 [Accept 30 × answer to a) i)]

very easy
very easy

b)

i)

ii)

2.5 or 5/2

75 [Accept 30 × answer to b) i)]

easy


easy

c)

i)

ii)

1/3 or 0.

18 [Accept 54 × answer to c) i)]

difficult


easy

 

Diagnostic and formative information: 
  

Common errors

Likely miscalculations

Likely reasons

a)ii)
b)ii)

70
60

30 + 40 = 30 + (60 - 20)
20 × 3 or 30 + 30 = 30 + (50 - 20)

   

c)i)

3

–3

24 ÷ 8

–(24 ÷ 8)

Uses the inverse of correct
calculation (8 ÷ 24).
Multiples by –1 because the photocopy is smaller and uses inverse of correct calculation.