Direct and Inverse Variation: Constant of variation

State the variation the following equation represents. $r=20t$  

• direct

• inverse

• none

State the variation the following equation represents. $r=\frac{t}{20}$  

• direct

• inverse

• none

State the variation the following equation represents. $r=\frac{20}{t}$  

• direct

• inverse

• none

State the variation the following equation represents. $rt=20$  

• direct

• inverse

• none

Find the constant of variation if y varies directly with x and y = 18 and x = 6

• 
  

   $k=3$  
  

•  $k=\frac{1}{3}$  

•  $k=2$  

•  $k=\frac{1}{2}$  

Find the constant of variation if y varies inversly with x and y = 12 and x = 2

• 
  

   $k=6$  
  

•  $k=\frac{1}{24}$  

•  $k=24$  

•  $k=\frac{1}{6}$  

Find the missing value for the following variation. If y varies inversely with x and y = 4 and x = 24, find y when x = 8.

• $y=3$

• $y=4$

• 
  

  $y=12$
  

• $y=6$

Find the missing value for the following variation. If y varies directly proportional to x and y = 16 and x = 64, find y when x = 40.

•  $y=6$ 

•  $y=8$ 

• 
  

  $y=12$
  

•  $y=10$ 

Find the constant of variation and write the function rule if y varies directly with x and y = 18 when x = 9.

• $k=\frac{1}{2},\ y=\frac{1}{2}x$

• $k=2,\ y=\frac{x}{2}$

• $k=2,\ y=\frac{2}{x}$

• 
  

  $k=2,\ y=2x$
  

Find the constant of variation and write the function rule if y varies directly with x and y = 12 when x = 6.

•  $k=72,\ y=\frac{72}{x}$ 

•  $k=72,\ y=72x$ 

•  $k=72,\ y=\frac{x}{72}$ 

• 
  

   $k=\frac{1}{72},\ y=\frac{x}{72}$