Direct Variation and Proportional Relationships

This video tutorial covers direct variation, explaining the equation y = kx and the constant of variation, k. It provides examples of solving word problems involving direct variation, such as calculating calories consumed and electricity costs. The video also discusses the difference between direct and non-direct variation, using examples like weight on Mars. The tutorial concludes with a preview of the next video on inverse variation.

What is the equation that represents direct variation?

• y = kx

• y = x + k

• y = k - x

• y = x / k

In the equation y = kx, what does 'k' represent?

• The difference between x and y

• The sum of x and y

• The variable

• The constant of variation

If Bob consumed 1320 calories by eating 10 brownies, how many calories are in one brownie?

• 132 calories

• 120 calories

• 150 calories

• 100 calories

Dave ate 2 brownies. How many calories did he consume if one brownie has 132 calories?

• 264 calories

• 132 calories

• 200 calories

• 150 calories

If 3 hours of electricity use costs 7 cents, what is the cost per hour?

• 2.33 cents

• 3.5 cents

• 7 cents

• 1.5 cents

How much will it cost for 11 hours of electricity use if 3 hours cost 7 cents?

• 26 cents

• 21 cents

• 30 cents

• 15 cents

A person weighs 115 pounds on Earth and 44 pounds on Mars. What is the constant of variation?

• 0.60

• 0.44

• 0.50

• 0.38

If Lola weighs 15 pounds on Earth, how much would she weigh on Mars?

• 4.5 pounds

• 5.7 pounds

• 6 pounds

• 7 pounds

Which of the following scenarios involves direct variation?

• Converting Fahrenheit to Celsius

• Total rise in temperature over time

• Price per pound of peanuts

• Distance traveled at constant speed

What is the key difference between direct variation and non-direct variation?

• Non-direct variation involves three variables

• Non-direct variation involves only one variable

• Direct variation involves three variables

• Direct variation involves only one variable