Perimeter and Area Relationships of Similar Triangles
September 13, 2013
What's Going On?
Materials Check
Who am I? Perimeter, Area and Pythagoras
Shortcut!
Learning Goal ­ I will recognize perimeter and area relationships between similar triangles.
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
R.A.F.T.
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
Who am I?
In our similar triangle unit we will need to know the difference between the 6 different types of triangles.
Let's see what you already know!
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
Triangle Definitions
Equilateral Triangle: A triangle with three equal sides AND all angles of 60o.
Scalene Triangle: A triangle with all three sides unequal.
Right Triangle: A triangle with one right (90°) angle.
Obtuse Triangle: A triangle with one angle more than 90°.
Isosceles Triangle: A triangle with two equal sides AND two equal angles.
Acute Triangle: A triangle with all three angles less than 90°
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
Perimeter, Area and Pythagoras
Two triangles are similar if they have the "same shape".
Basically, one is an enlargement of the other. If two triangles are similar, their angles are ______________.
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
Perimeter, Area and Pythagoras
These two triangles are similar... D
A
4 cm
B
5 cm
3 cm
8 cm
C
E
F
ABC ~ DEF
We name triangles by their vertices!
"similar"
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
Perimeter, Area and Pythagoras
These two triangles are similar... D
A
10 cm
5 cm
4 cm
B
3 cm
8 cm
C
E
Perimeter:
Perimeter:
Area:
Area:
6 cm
F
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
Perimeter, Area and Pythagoras
So the perimeter of DEF is DOUBLE the perimeter of ABC
But the area of DEF is QUADRUPLE the area of ABC...
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
We can see that the perimeter has been doubled and the area has been quadrupled!!
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Perimeter and Area Relationships of Similar Triangles
September 13, 2013
Perimeter and Area of Similar Triangles
(a similar triangle!!)
If one triangle of the same shape has double the perimeter of the original triangle, the resulting area of the triangle would be quadrupled (four times the area of the original)
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