Skip to lesson

Choose “Save as PDF” in the print dialog to keep a copy.

Cogito

Grade 8 Math · Chapter 2 · Lesson 2

Practice Worksheet

Similar Figures

Same shape, different size.

10 problems · about 19 minutes · 8.G.A.4, 8.G.A.5

NameDate

Figure — use these to answer the problems

Matching sides of similar figures form one ratio, the same for every pair.
A ratio table for 3 to 6
Small figureLarge figure
36
612
918
Small figureLarge figure0036612918
Side on the small one3
Matching side on the large one6
Scale it up by3
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

2 problems

  1. From “Dilations”

    A side of 9 dilated by 3. New length?

    Answer

  2. From “Sequences of Moves”

    Rotated 90° three times. Total turn in degrees?

    Answer

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. Similar figures. 4 matches 10. Another side is 6. Its match?

    Answer

  2. What is true of similar figures?

    • Equal angles and sides in one ratio.
    • Everything is equal.

  3. Similar figures. 2 matches 8. Another side is 5. Its match?

    Answer

  4. Similar figures. 6 matches 9. Another side is 4. Its match?

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. Two triangles share angles of 50 and 60. Are they similar?

    • Yes.
    • No.

  2. Similar figures. 5 matches 15. Another side is 7. Its match?

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

2 problems

  1. The Similar Pair

    Similar triangles. 3 matches 12, and another side is 5. What is its match?

    Answer

  2. The Angles

    Two similar triangles. One angle is 63 degrees. What is the matching angle?

    Answerdegrees