Proportionality in Equations

What is the formula for a proportional relationship?

• y=kx

• y=k/x

• z=ykx

• y=ky

In the equation y = 14x, what is the constant of proportionality?

• y

• x

• 14

If the constant of proportionality is 10, which of the following is the correct proportional equation?

• 10=kx

• 10=k

• y=10k

• y=10x

Which equation matches the graph?

• y = 8x

• y = 1x

• y = 3x

• y = 16x

Write how to find the proportion of

2:8 :: 25:625

(Do not give space first right the means than the extremes.)

Mathematical Equivalence

ON

Proportional or Not Proportional?

• Proportional

• Not Proportional

Is this a proportional equation?  Why?

• It is not proportional because it doesn't have a constant.

• It is not proportional because it doesn't have a constant rate of change.

• It is proportional because if x = 0, y = 0.

• It is proportional because it has a y intercept.

Which equation shows a proportional relationship between x and y? (a)  

• y = 3x + 9

• y = 1/2x

• y = 1/2x - 2

• y = x2

Does each equation represent a proportional relationship? Choose Yes or No.

y = 13x - 7 ​ (a)  

y = 13x ​ (b)  

• no

• yes

Answer explanation

The first equation y = 13x - 7 does not represent a proportional relationship because it has a y-intercept that is not zero. A proportional relationship must have a y-intercept of zero. The second equation y = 13x does represent a proportional relationship because it has a y-intercept of zero.

Tags

CCSS.MATH.CONTENT.7.RP.A.2.b

CCSS.MATH.CONTENT.7.RP.A.2.c

What is the constant of proportionality for this table?

• 1/9

• 9

• 8