ABCD is a square. Two equilateral triangles AED and BFC have been constructed on the sides AD and BC respectively. Prove that triangle ABF is congruent to triangle CDE.

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Step-by-step explanation:

Hi,

Let's plot the figure, 1 square and 2 equilateral triangles.

1) Let's remember all the angles we already know, from the square and the equilateral triangle from their respective definition.

In other words:

Statement                               Reason                          

  Given

2) We have two triangles ABF and CDE

3) The Side, Angle Side Congruence Theorem assures us that both triangles are congruent. When there are two known legs (4 cm and 4 cm) of each  triangle, and their respective formed angle is also known (150º). Therefore, these two triangles are both congruent.

Statement                                                   Reason

idk

step-by-step explanation: