We have two corresponding parts of the similar figures. Their diagonals measure 11 and 7 feet. Let's use these to find the scale factor.
Scale Factor: 11/7
The scale factor for our figures is 117. Using this, we can find the ratio of the areas.
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Scale Factor & & Ratio of the Areas [0.8em]
11/7 & ⇒ & 11^2/7^2= 121/49
Finally, let x be the area of the green quadrilateral. We will write and solve a proportion using the ratio of the areas and the area of the blue figure, which is 42ft^2.
