Answer:
the constant proportionality means the ratio between two directly proportional quantities.
so the constant proportionality will be 7.5÷6=1.25 or 10÷8=1.25 or 12.5÷10=1.25
constant proportionality should be same all through because it's a constant
(3 x 10) x 8 = 3 x (10 x 8)
this is called the associative property of multiplication.
it states : (a * b) * c = a * (b * c)