Starter Questions
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Starter Questions Starter Questions
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Starter Questions. Similar Figures. Learning Intention. To explain how the scale factor applies to similar figures. Similar Figures. shapes are similar only when. Corresponding sides are in proportion. AND. Corresponding angles are equal. - PowerPoint PPT Presentation
Transcript of Starter Questions
Starter QuestionsStarter Questions
Learning IntentionLearning Intention
To explain how the scale factor applies to similar figures.
Similar FiguresSimilar Figures
Similar FiguresSimilar Figures shapes are similar only when
• Corresponding sides are in proportion
AND• Corresponding angles are equal
All these rectangles are not similar to one another since only condition 2 is true
Similar FiguresSimilar FiguresScale Factor
Scale Factor is the number used as a multiplier in enlarging / reducing shapes
To calculate the scale factor
In similar shapes…
…divide the length by length, and where possible breadth by breadth
Corresponding sides are in proportion AND corresponding angles
are equal
Similar FiguresSimilar FiguresThe rectangles below are similar: Find the enlargement scale factor that maps A to B
A
B
8cm 16cm
5cm10cm
E.S.F = 16 ÷ 8 = 2
E.S.F will always be
greater than 1
Similar FiguresSimilar FiguresThe rectangles below are similar: Find the enlargement scale factor that maps A to B
A
B
8cm 12cm
5cm7.5cm
E.S.F = 12 ÷ 8 = 1.5
E.S.F will always be
greater than 1
Similar FiguresSimilar FiguresIf we are told that two objects are similar, and we can
calculate the scale factor, then we can calculate the value of an unknown side
These 3 rectangles are similar. Find the unknown sides
A
BC
3cm
8cm24cm
xcm13.5cm
ycm
Similar FiguresSimilar Figures
If we are told that two objects are similar, and we can calculate the scale factor, then we can calculate the value of
an unknown side
These 3 rectangles are similar. Find the unknown sides
A
BC2.1cm
5.6cm
7.14cm
xcm26.88cm
ycm
Given the shapes are similar, find the values y and z ?
Scale Factor applies to ANY SHAPES that are mathematically similar.
15 cm
3 cm
7 cm2cm
yz
6 cm
1.4 cm
Similar FiguresSimilar Figures
Given the shapes are similar, find the values a and b ?
Scale Factor applies to ANY SHAPES that are mathematically similar.
8 cm
7.5 cmb
10 cm
4 cm
2cm
a
3 cm
Similar FiguresSimilar Figures
Similar FiguresSimilar Figures
The rectangles below are similar: Find the reduction scale factor that maps B to A
A
B
5cm 20cm
3cm12cm
R.S.F will always be less than 1
Similar FiguresSimilar Figures
If we are told that two objects are similar, and we can calculate the scale factor, then we can calculate the value of
an unknown side
These 2 rectangles are similar. Find the unknown sides
A
B4mm
x mm
16mm
28mm
Now try Ex 5.1Ch 4 Pg 75
Similar FiguresSimilar Figures
