Let x be the width of the border that will be added. Begin by finding the area of the border in terms of x. To do that you can divide border into four rectangles.
Length: 20 in Width: 15 in
Practice makes perfect
Enola wants to add a border to her painting, distributed evenly. Let x be the width of the border that will be added.
Let's find the area of the border in terms of x by dividing the border into four rectangles.
Area of a rectangle is the product of its length and width. With this, the area of the border can be represented as the sum of the areas of the four rectangles.
A_R=x(10+2x)+x(10+2x)+x(15)+x(15)
Let's simplify it!
The result tells that the width of the border is either 52 in or -15 in. Because a measure cannot be negative, we can say that the width must be 52 in. With this, we can find the dimensions of the painting with the border included.
Length:& 15+2x ⇒ 15+2( 5/2)=20
Width:& 10+2x ⇒ 10+2( 5/2)=15
