8th Grade Dilations and Similar Figures Quiz: 10 Questions with Explanations

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This dilations similarity quiz for 8th Grade covers dilations and similar figures (Common Core 8.G.A.3, 8.G.A.4), with a free PDF to print.

Pick the best answer for each of the 10 questions about dilations, scale factors, similar figures and similarity transformations (Common Core 8.G.A.3 and 8.G.A.4). Read each question carefully, then read the explanation to learn from any mistake.

Grade 8 · Common Core State Standards: 8.G.A.3, 8.G.A.4

Dilations similarity quiz: 10 questions

Question 1
What is the image of \((5, 2)\) after a dilation from the origin with scale factor 3?

Question 2
A dilation maps \((4, 6)\) to \((2, 3)\). What is the scale factor?

Question 3
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Triangle ABC with area 1.

Triangle ABC has area 1 square unit. It is dilated with scale factor 4. What is the area of the image?

Question 4
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Each side of the large triangle is 2 times the matching side.

What is the scale factor from the small triangle to the large triangle?

Question 5
Which is preserved by a dilation?

Question 6
Two similar triangles have shorter sides 4 and 10. The longer side of the smaller triangle is 6. What is the longer side of the larger triangle?

Question 7
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Sun rays make similar right triangles.

Using the diagram, how tall is the tree?

Question 8
A dilation with scale factor 1 produces a figure that is

Question 9
Rectangles 3 by 5 and 6 by 9 are

Question 10
A photo 5 inches by 7 inches is enlarged by a factor of 3. What is the new width (the 5)?

Remember

Remember
  • Dilation from the origin: \((x, y) \to (kx, ky)\).
  • \(k > 1\) enlarges; \(0 < k < 1\) reduces; \(k = 1\) leaves the figure unchanged.
  • Angles stay equal; side lengths multiply by \(k\); area multiplies by \(k^{2}\).
  • Similar figures have equal angles and proportional sides.
  • Use \(\frac{\text{new}}{\text{old}} = k\) to find missing lengths.

How to use this dilations similarity quiz

Answer each question, read the explanation that appears, and keep track of your score. A score of 8 out of 10 or more means you are ready for the test.

Download the dilations similarity quiz as a PDF with the button below and keep it with your notes.

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8th Grade Dilations and Similar Figures Quiz: 10 Questions with Explanations

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