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What the frick is this. Help. Can someone explain how to do these?

 Jun 29, 2018
 #1
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Assuming that these are similar figures...and that the side of the larger triangle with a length of 6  corresponds to the side of the smaller  triangle with a length of 2

 

The  scale factor of the larger triangle to the smaller  is just  the above ratio  = 6/2  = 3/1

This is the linear scale factor for  any dimension....all corresponding sides of the larger figure to the smaller  wil have this ratio...also...the height of the larger triangle to the smaller wioll also have this ratio

 

Perimeter is a linear measure...so ...the ratio of the perimeters will just  be  the same  ratio    3 : 1  

 

The ratio of the areas will be  the square of the scale factor  = (3/1)^2  = 9/1  = 9 : 1

 

So...the area of the the blue triangle will be :

 

Area of the smaller  triangle * (scale factor)^2  =

 

2  * (3/1)^2  =

 

2 * 9  =

 

18 ft^2

 

To  see this last part a litle more clearly

Note that the area of the smaller triangle  = (1/2) base * height  = (1/2) b * h

But since each dimension of the larger triangle is 3 times that of the smaller...its area  is

(1/2) ( 3* base of smaller triangle) ( 3 * height of smaller triangle)  =

(1/2) (3 b) (3 h)  = (1/2) 9 bh  =  9 [ (1/2) bh ] =   9 times [ the area of the smaller triangle]

 

Does that make some sense ???

 

cool cool cool

 Jun 29, 2018

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