How do you know whether two quantities x and y are proportional? a. Every ratio yx for related pairs of x and y is equivalent.
b. Every sum x + y is the same for related pairs of x and y.
c. Every x term is a multiple of the previous term.
d. Every difference x – y is the same for related pairs of x and y.

a. Every ratio yx for related pairs of x and y is equivalent.

Step-by-step explanation: The proportionality between two variables x and y is established using the proportionality relation.

x = ky where k is a constant and k = x / y. Hence every ratio of both numbers for a rated pair are equivalent once x and y ≠ 0

the value of x is 90 - 20 aka 70*, these are complementary angles

step-by-step explanation: