Contextes de border pour le sens abstrait
A photograph is 7 inches long and 5 inches wide. It is surrounded
by a border of uniform width. If the area of the border alone is
64 sq. inches, what is the width of the border?
--
Draw yourself a diagram of a rectangle 7 inches by 5 inches. Now add a
uniform border all around this rectangle. Call the width of this
border x. Now we need to find the area of just the border. One way to
do it is to draw a square in each corner. The area of one square is
--
so that x = -8 or x = 2. We reject the negative solution. Our answer
is x = 2. Therefore, the width of the border is 2 inches.