SOLUTION: A rectangular portrait measures 50 cm by 70 cm. It is surrounded by a rectangular frame of uniform width. If the area of the frame is the same as the area of the portrait, what is

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Question 1084821: A rectangular portrait measures 50 cm by 70 cm. It is surrounded by a rectangular frame of uniform width. If the area of the frame is the same as the area of the portrait, what is the approximate width of the frame?

Answer by chen(11) About Me  (Show Source):
You can put this solution on YOUR website!
The area of the portrait is 50x70 = 3500 square cm
Let's call w the width of the frame.
Its area is 2*(70+2*w)*w+2*50*w =
140%2B4%2Aw%5E2%2B100%2Aw=3500
then dividing by 4:
w%5E2%2B25%2Aw-840=0
By solving the equation we get w = around 19cm