# Why do we use line graphs?

Line graphs can also be used to compare changes over the same period of time for more than one group. Pie charts are best to use when you are trying to compare parts of a whole. They do not show changes over time. Bar graphs are used to compare things between different groups or to track changes over time.
A.

### What does it mean when there is a straight line on a graph?

mx y = and this is the equation of a straight line through the origin. This is why the graph of x y 4 = is a straight line. By definition: A straight line is a graph which has a constant gradient m.
• #### What is the equation of the straight line in the graph?

The general equation of a straight line is y = mx + c, where m is the gradient, and y = c is the value where the line cuts the y-axis. This number c is called the intercept on the y-axis. The equation of a straight line with gradient m and intercept c on the y-axis is y = mx + c.
• #### Is a straight vertical line a function?

To use the vertical line test, take a ruler or other straight edge and draw a line parallel to the y-axis for any chosen value of x. If, alternatively, a vertical line intersects the graph no more than once, no matter where the vertical line is placed, then the graph is the graph of a function.
• #### What does the gradient of the line represent?

Slope (or Gradient) We call m the slope or gradient of the line. It represents the change in y-value per unit change in x-value. For example, consider the line given by the equation y = 2x + 1. Here are some points on the line.
B.

### What does the point on a line of a graph represent?

A point-to-point graph, also called a line graph, is a pictorial rendition of data in which specific values of a function are plotted as dots on a coordinate plane. Adjacent pairs of dots are connected by straight lines. Finally, each adjacent pair of points is connected by a solid, straight line segment.
• #### What is the difference between a line graph and a scatter plot?

Scatter plots show how much one variable is affected by another. Line graphs are like scatter plots in that they record individual data values as marks on the graph. The difference is that a line is created connecting each data point together. In this way, the local change from point to point can be seen.
• #### Do you read a graph from left to right?

Let's take a look at a few notes that will help you make sure your graphs are correct when graphing linear equations. When reading the graph from left to right, the line rises if the slope is positive. When reading the graph from left to right, the line falls if the slope is negative.
• #### How do you draw a graph?

How to Draw a Graph
1. Draw the x axis. Make a horizontal line on the paper.
2. Draw the y axis. Make a vertical line that passes through the origin of the x axis.
3. Calculate the values of y for several values of x.
4. Mark the ordered pairs on the graph.
5. You have created a graph of the function f(x) = 2x.

Updated: 2nd November 2019