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CALCULATE THE AREA OF BASIC POLYGONS DRAWN ON A COORDINATE PLANE • A coordinate plane is a grid on which points can be plotted. • The horizontal axis is labeled with positive numbers to the right of the vertical axis and negative numbers to the left of the vertical axis. • The vertical axis is marked with positive numbers above the horizontal axis and negative numbers below the horizontal axis. • Points are plotted using coordinates which indicate its location: (5, 7) or (-4, 3) or (-1, -6) • Polygons can be plotted and their sides measured by using the coordinates. • The area of the region within the sides of the polygon is calculated by using the formula: Area = length X width © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.

How to calculate the area of a basic polygon drawn on a coordinate plane: • Begin by plotting the four points which will be the corners of the polygon. • The first number in the coordinate indicates the point’s position relative to the horizontal axis and the second number places the point relative to the vertical axis. o A point located at (6, 3) is 6 spaces to the right of the vertical axis and 3 spaces above the horizontal axis. o A point located at (2, -7) is 2 spaces to the right of the vertical axis and 7 spaces below the horizontal axis • Connect the four points (corners). • Use the grid to measure the 4 sides of the polygon. • Use the formula A = length X width to calculate the area. Examples • The coordinates for a polygon are: (2, 6), (6, 6), (2, 10) and (6, 10) o The length is from 2 to 6 along the horizontal axis or 4 units o The width is from 6 to 10 along the vertical axis or 4 units o The polygon is a square that measures 4 by 4 o A = l x h → A = 4 x 4 = 16 sq. units • The coordinates for a polygon are: (3, 4), (15, 4), (3, 12 ) and (15, 12) o The length is from 3 to 15 along the horizontal axis, 12 units o The width is from 4 to 12 along the vertical axis, 8 units o The polygon is a rectangle that measures 12 by 8 o A = l x h → A = 12 x 8 = 96 sq. units © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.

Try This! Plot the points for each polygon and calculate the area: (-3, 5), (-8, 5), (-3, 10), (-8, 10) _______________________________ (-2, -5), (-8, -5), (-2, -11), (-8, -11) _______________________________ (8, -3), (15, -3), (8, -9), (15, -9) _______________________________ (2, 5), (10, 5), (2, 13), (10, 13) _______________________________ (-2, 3), (-5, 3), (-2, 10), (-5, 10) _______________________________ © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.