Ch 15 introduces graphical representation of data and equations. Students learn to read and draw line graphs, plot points on a coordinate plane, and graph simple linear equations.
Bar graphs represent categorical data. Pie charts show composition. Line graphs show changes over time (connect data points). Histograms represent frequency distribution of continuous data.
A coordinate plane has two perpendicular axes: x (horizontal) and y (vertical), meeting at the origin (0,0). Any point is represented as an ordered pair (x, y). The x-coordinate tells horizontal position, y-coordinate tells vertical position.
A linear equation y = mx + c produces a straight-line graph. Plot at least two points satisfying the equation, then connect them. The graph of x = a is a vertical line; y = b is a horizontal line.
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Because its graph is a straight line. Linear means "related to a line." Any equation of the form y = mx + c (degree 1) produces a straight line when graphed.
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