Purpose: To solve word problems that involve area. Homework: Finish teaching worksheet. Pg all.
Example #1 A rectangle is 3 times long as it is wide. If the length is increased by 6 and the width by 8, the area is increased by 108. Find the original dimensions. You may want to draw the rectangles first. 3x 3x + 6 x x + 8
Example #1 (cont.) You know from the problem that when you increase the dimensions the area is also so set up the equation like this: Original Area + Increase = New Area 3x(x) = (3x + 6)(x + 8) FOIL 3x² = 3x² + 30x x² CANCEL 108 = 30x + 48 Subtract = 30x x = 2 Original was 2 x 6
Example #2 A painting is 10 in. longer than is wide and is bordered by a 3 in. frame on all sides. If the area of the frame alone is 402 in.², what are the dimensions of the painting. Draw a diagram to help you. By putting a frame all around you add 6 to the L and W
Example #2 (cont.) Area of Picture + Frame = Total Area x(x + 10) = (x + 6)(x + 16) FOIL x² + 10x = x² + 22x + 96 x² CANCEL 10x = 22x + 96 Subtract 10x 402 = 12x + 96 Subtract = 12x Divide by = x so W = 25.5 and L = 35.5