This would be 6C3
= 6*5*4
---------- = 20 answer
3*2*1
The angles are the only constraint here that counts. If one of the three interior angles of a supposed triangle is 50 degrees and another is 80 degrees, then the third angle must be 50 degrees. Thus, we have a 50-50-80 triangle, which is isosceles though not a right triangle. If 4 feet is a measure of one of the equal sides of a supposed triangle, then obviously the adjacent side also has measure 4 ft.
The set of angles remains the same (50-50-80), but subject to the constraint mentioned above, the measure of any one of the sides has infinitely many possible values, so long as those values are positive.
A ∩ B = {3, 6, 9, 12} ∩ {2, 4, 6, 8, 10, 12}
= {6, 12}
12/16,
6/8,
3/4, and
45/60
are all equivalent to 24/32.
Now that I've listed those four, there are
only an infinite number of others remaining.
