Algebra 2 - Using direct variation and proportions to find your missing value

The video tutorial explains the concept of direct variation, represented by the equation y = KX. It demonstrates how to solve a problem involving direct variation by setting up a proportion and using cross multiplication. The example given is finding the value of X when Y is 3, given that Y is 4 when X is -2. The solution involves setting up the proportion 4/-2 = 3/X, applying cross multiplication, and solving for X, which results in X = -3/2.

What is the formula for direct variation?

• y = X + K

• y = X / K

• y = KX

• y = K + X

If y = 4 when X = -2, what is the constant of variation (K)?

• 1/2

• -1/2

• 2

• -2

How can you express the relationship between y and X in a direct variation?

• As a ratio

• As a difference

• As a sum

• As a product

What is the first step in solving a proportion using the cross product method?

• Add the terms

• Multiply the terms diagonally

• Subtract the terms

• Divide the terms

What is the value of X when y = 3, given that y = 4 when X = -2?

• -3/2

• 3/2

• -2/3

• 2/3