Question

The graph below represents the price of sending text messages using the services of a phone company. What is the constant of proportionality?

8
14
16
48

Answer 1

16

Explanation:

The reason the answer is 8 is because if you see it is going up by 16's. If you see 0,16,32,48,64 all be 16's.

Answer 2

8

Explanation:

The equation is of the form

y = kx ← k is the constant of proportionality

To find k use the slope formula

k = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (0, 0) and (x₂, y₂ ) = (2, 16) ← 2 points on the line

k =
`(16-0)/(2-0)` =
`(16)/(2)` = 8