Square and Inscribed Equilateral Triangle

 

 

Given square WXYX and equilateral triangle ABZ, find the ratio of the areas of ∆BYZ  and  ∆ABX.  

 


 Let the sides of the equilateral  triangle each be of length c  and let the side of the square be of length 1.    If we let the legs of isosceles right triangle ABX be of length, that is  BX = a and AX = a, then BY = 1-a.   

 



The area of a right triangle is half the product of the legs so the ratio of the areas of ∆BYZ and ∆ABX is

 

 


Hint?  Or,  how about a GSP sketch?      If desperate,  see one solution.

 


 

Extension/alternative:    Using geometry, show that

 

         Area triangle AXB =  Area triangle AWZ  +  Area triangle BYZ

 

Hint?    See  GSP Sketch.

 


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