



 
Hi Riley, You are correct that in your example the scale factor is 2. The scale factor refers to length (a one dimensional concept) and in your example the 5 by 10 rectangle has a perimeter of 5 + 10 + 5 + 10 = 30 units which is a length measurement. You didn't give units but I am going to assume the units are centimeters so the perimeter is 30 centimeters. Thus the larger rectangle has a perimeter of (the scale factor) × 30 = 2 × 30 = 60 centimeters. You can check this since the larger rectangle has perimeter 10 + 20 + 10 + 20 = 60 centimeters. Area is a two dimensional concept and the units are square centimeters. The area of the small rectangle is 5 × 10 = 50 cm^{2} so the area of the large rectangle is
Again in your example you can check this since the large rectangle is 10 cm by 20 cm so its area is 10 × 20 = 200 cm^{2}. The result is that for length (one dimensional) measurements you multiply by the scale factor and for area (two dimensional) measurements you multiply by the square of the scale factor. Good luck on the test,  


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