1) Since the width is 6 inches longer than the height, we can express the width as w = 6 + h. The equation for the area of a rectangle is w*h so the area of this canvas will be (h+6)(h) = h^2 + 6h.
2) when Nicholas adds in the silver frame, there are additional rectangles, namely 2 with area 4(6+h) and 2 with area 4h, and then 4 squares of area 16. Thus we can simply add these areas together.
Area of canvas + Area of frame = (h+6)(h) + (2)(4)(6+h) + 2(4)(h) + 4(16) = h^2 + 22h + 112.
3) let's express the width of the frame as a variable. When we do this, we will still have:
Area of canvas + Area of frame = (h+6)(h) + 2r(6+h) + 2rh + 4r^2 = h^2+6h+12r+4hr+4r^2.
This is what we have, and we want to find a value of r such that
h^2 + 6h + 4hr + 12r + 4r^2 = h^2 + h(6 + 4r) + 12r + 4r^2 turns into h2+ 12h + 27.
We can see that this will be true then: 6+4r = 12, and 12r + 4r^2 = 27.
Let's solve for r with the linear equation We attain that r = 1.5.
Lets solve for r in the quadratic 12r + 4r^2 = 27. When we apply the quadratic formula we see r = -4.5, 1.5.
r cannot be negative so we toss out -4.5.
Furthermore, notice that r = 1.5 is repeated in both! This is the answer.
So to recap,
1) Express the width in terms of the height, then multiply them together since the width of a rectangle is width*height.
2) add in the additional area gained from the frame. This will be 4 rectangles and 4 squares (draw it out and you will see)
3) Express the length of the frame as another variable. Write out the general equation, match terms, and solve the resulting system of equations. In general, if everything is done correctly you should get two matching solutions.
Hope this helps!
Darius B.
04/15/22