Question

Complete the reason for step 4 in the proof below.

Answer 1

never understood Side Angle Side or Side Side Angle or any of that matter

Answer 2

In steps 2 and 3 they prove TWO angles of one triangle is equal to TWO angles of another triangle. And in step 3 they conclude the two triangles are similar. Therefore, ....

Answer 3

Look at what all they have proved before concluding the two triangles are similar.
In step 2 they say angle D of first triangle equals angle F of second triangle.
In step 3 they say angle E of one triangle equals angle G of second triangle.
So far they have proved TWO angles of the first triangle is equal to TWO angles of the second triangle. In the next step they conclude the two triangles are similar. So far we have not made any reference to the side of the triangle or the third angle of the triangle. Only two angles have been proven so far.

Answer 4

Angle-Angle Similarity Postulate
which states if TWO angles of one triangle are equal to TWO angles of another triangle then the triangles are similar.