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The right triangle below is the image of a right triangle that was dilated by a scale factor of 2. Find the

perimeter of the preimage, the original right triangle, before its dilation. Figures are not necessarily
drawn to scale.
30
34
16

The right triangle below is the image of a right triangle that was dilated by a scale-example-1
User Ialm
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1 Answer

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The perimeter of the original right triangle is 40 units. This is determined by halving the perimeter of the dilated triangle, as each side length in the original triangle is half the corresponding length in the dilated triangle.

To find the perimeter of the original right triangle, we can use the scale factor and the perimeter of the dilated triangle.

Step 1: Calculate the perimeter of the dilated triangle.

The perimeter is the sum of the side lengths: 30 + 34 + 16 = 80 units.

Step 2: Apply the scale factor to find the side lengths of the original triangle.

Each side length of the original triangle is half the length of the corresponding side in the dilated triangle. Therefore, the sides of the original triangle are:

Short leg: 30 units / 2 = 15 units

Long leg: 34 units / 2 = 17 units

Hypotenuse: 16 units / 2 = 8 units

Step 3: Calculate the perimeter of the original triangle.

Add the side lengths of the original triangle: 15 units + 17 units + 8 units = 40 units.

Therefore, the perimeter of the preimage, the original right triangle, is 40 units.

Alternatively:

We can use the fact that the perimeter of a dilated figure is equal to the perimeter of the original figure multiplied by the scale factor. In this case, the perimeter of the original triangle is 1/2 the perimeter of the dilated triangle:

Perimeter of original triangle = Perimeter of dilated triangle / Scale factor

Perimeter of original triangle = 80 units / 2

Perimeter of original triangle = 40 units

Therefore, both methods lead to the same answer: the perimeter of the original right triangle is 40 units.

User NeverStopLearning
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