If you know an original dimension and a scale factor of dilation, you can use that information to determine measurements in the dilated figure.
Click on the screenshot below and use the interactive tool to dilate rectangle A. Use the properties of a rectangle to calculate the perimeter of A. Then use the dilated dimensions, as well as the properties of a rectangle, to calculate the perimeter of B. Click on the "measures" tab to check your answers.
What is the ratio of the dilated perimeter to the original perimeter?
Interactive popup. Assistance may be required. The ratio of the dilated perimeter to the original perimeter is the same as the scale factor.
Now use the same interactive, but change the shape to a triangle. Move the vertex to make a right triangle, and dilate triangle A. Use the properties of a right triangle to calculate the perimeter of A. Then use the dilated dimensions, as well as the properties of a right triangle, to calculate the perimeter of triangle B. Click on the "measures" tab to check your answers.
What is the ratio of the dilated perimeter to the original perimeter?
Interactive popup. Assistance may be required. The ratio of the dilated perimeter to the original perimeter is the same as the scale factor.
Parallelogram ABCD is dilated by a scale factor of 0.75 in order to generate parallelogram PQRS.
1. Determine the lengths of sides PQ and SP in parallelogram PQRS.
Interactive popup. Assistance may be required. PQ = 2.7 centimeters
2. Determine the perimeter of parallelogram PQRS. Use the grid below to record your answer. Type your answer in the boxes in front of and behind the decimal. Click inside each box to enter the numeral that belongs in the box. Click the bubble beneath the numeral to shade the bubble that matches the numeral. Incorrect portions of your answer will be shaded gray.