10) Enlarging by a factor of 7 corresponds to an increase by a factor of [tex]7^2[/tex] for the area, or 49. The new rectangle has area 980 square-inches.
To verify, let's say the dimensions of the original rectangle are [tex]5 \ in \times 4 \ in[/tex]. We increase each dimension by a factor of 7 to get [tex]35 \ in \times 28 \ in [/tex]. This new area is 980 square-inches.
11) We use the same concept. Increasing by a factor of 0.6 corresponds to increasing the area by [tex]0.6^2[/tex] (n.b., an increase by a factor less than 1 is shrinking). Original area is [tex](30)(10)( \frac{1}{2})=150 [/tex]. New area is [tex](150)(0.36)=54 \ cm^2[/tex].
12) We multiply 15 by 11/30 to get 5.5 ft. We multiply 8.25 by the same factor to get 3.025 ft. The area is [tex]5.5 \ ft \times 3.025 \ ft = 16.6375 \ ft^2[/tex].
