When would there be only four different equations for a set of math mountain numbers?

Only when any equation you find among those numbers can be simplified into one of the four main equations, which means you only have four different true statements and lots of equivalences. 20 = 40 - 20. As the two addends are the same, so there would be only four different equations for a set of math mountain numbe

Step-by-step explanation:

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

ummm seems that u didnt post the attachement !