Proportions with Linear Equations

Solve the proportion.

• k=5

• k=3.3333333

• k=60

• k=90

Solve for x

• 1/2

• 25/8

• 11

• 53/4

To solve proportions, you must...

• Multiply the numerators with the numerators

• Cross multiply

• Set equations equal

• Multiply by the denominator

Which of the following graphs is 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 of 22.

Which best describes the equation?y = 75x (a)  

• Proportional

• Nonproportional

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

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

The number of t-shirts that Kim can make varies directly with the amount of time she spends making shirts. She makes 8 shirts in $ \frac{1}{4} $ hours. How many t-shirts can she make in 9 hours?

• 288

• 72

• 144

• 36