## What does direct mean in math?

1: mathematical relationship between two variables that can be expressed by an equation in which one variable is equal to a constant times the other. 2: an equation or function expressing direct variation — compare inverse variation.

## What is direct variation and example?

For example, if y varies directly as x, and y = 6 when x = 2, the constant of variation is k = = 3. Thus, the equation describing this direct variation is y = 3x. Example 1: If y varies directly as x, and x = 12 when y = 9, what is the equation that describes this direct variation?

## What is direct variation in algebra?

Direct variation describes a simple relationship between two variables. We say y varies directly with x (or as x, in some textbooks) if: y=kx. for some constant k, called the constant of variation or constant of proportionality.

## How do you know if it is a direct variation?

A direct variation is when x and y (or f(x) and x) are directly proportional to each other For example, if you have a chart that says x and y, and in the x column is 1, 2 and 3, and the y column says 2, 4 and 6 then you know it’s proportional because for each x, y increases by 2

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## What are the 4 types of variation?

Examples of types of variation include direct, inverse, joint, and combined variation.

## How do you answer direct variation?

Direct variation problems are solved using the equation y = kx. When dealing with word problems, you should consider using variables other than x and y, you should use variables that are relevant to the problem being solved.

## How do you teach direct variation?

Solving a Direct Variation Problem

1. Write the variation equation: y = kx or k = y/x.
2. Substitute in for the given values and find the value of k.
3. Rewrite the variation equation: y = kx with the known value of k.
4. Substitute the remaining values and find the unknown.

## What is an example of joint variation?

When a variable is dependent on the product or quotient of two or more variables, this is called joint variation. For example, the cost of busing students for each school trip varies with the number of students attending and the distance from the school.

## What are some examples of direct variation in real life?

Some examples of direct variation problems in real life:

• The number of hours you work and the amount of your paycheck.
• The amount of weight on a spring and the distance the spring will stretch.
• The speed of a car and the distance traveled in a certain amount of time.

## Does a direct variation have to go through the origin?

The graph of a direct variation always passes through the origin, and always has a slope that is equal to the constant of proportionality, k.

## Is direct variation the same as slope?

As you can see, direct variation is set up in slope intercept form. y = kx is very similar to y = mx. With direct variation, the y-intercept is 0, so you won’t have the “+b” portion of slope intercept form. The constant of variation (k) is very similar to the slope in slope intercept form.

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## How can you tell if a graph is a direct variation?

A graph shows direct variation if it goes through the origin, (0,0). The equation is y=kx, where k is a constant, which is apparent when we write the equation as yx=k. In slope-intercept form, the equation would be y=mx+b, where m=k, and b=0.

## What is the difference between direct and joint variation?

Direct Variation, where one variable is a constant multiple of another. Inverse or Indirect Variation, where when one of the variables increases, the other one decreases (their product is constant) Joint Variation, where more than two variables are related directly.

## How do you know if an equation is direct or inverse?

Numerically: Direct Variation: Because k is positive, y increases as x increases. So as x increases by 1, y increases by 1.5. Inverse Variation: Because k is positive, y decreases as x increases.