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Grade 7 · Math

7th grade Similar shapes: matching sides and angles worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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Similar shapes: matching sides and angles

Grade 7 Math Worksheet - Building Confidence

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Circle the best answer, or write your answer on the line.

  1. One row 30 | ?, with the arrow × 5 from A to B. Bo builds a model tent (A) of a real tent (B). The scale factor from A to B is 5. The model is 30 cm tall. How many cm tall is the real tent?

  2. One row 45 | ?, with the arrow × 2 from A to B. Esme's small kite (A) and big kite (B) are similar. The scale factor from A to B is 2. The small kite is 45 cm wide. How many cm wide is the big kite?

  3. One row 20 | ?, with the arrow × 10 from A to B. Jun makes a model door (A) of a real door (B). The scale factor from A to B is 10. The model is 20 cm tall. How many cm tall is the real door?

  4. Read this first

    Use the table

    A, cmB, cm
    520 for the matching sides
    4? for the other sides

  5. Noah builds a small ramp (A) and a bigger ramp (B), similar triangles. A's ground length is 5 cm and B's is 20 cm. A is 4 cm tall. How many cm tall is B?

  6. One row 20 | 100 for the matching sides, with a box for the multiplier from A to B. Ren's model table (A) is 20 cm long, and the matching side of the real table (B) is 100 cm long. What is the scale factor from A to B?

  7. One row 3 | 30 for the widths across, with a box for the multiplier from A to B. Tala bakes a small round cookie (A) and a giant one (B), similar shapes. A is 3 cm across and B is 30 cm across. What is the scale factor from A to B?

  8. One row 25 | 200 for the matching sides, with a box for the multiplier from A to B. Zee's dollhouse bed (A), with its tiny pillow, is 25 cm long, and the matching side of the real bed (B) is 200 cm long. What is the scale factor from A to B?

  9. Ari sees two similar tent flaps, A and B. Every side of B is 3 times as long as A's. A has an angle of 50° at the top. How big is B's matching angle?

  10. Bo traces two similar sails, A and B. Every side of B is 2 times as long as A's. A has an angle of 70° at the top. How big is B's matching angle?

  11. Esme draws two similar roofs, A and B. Every side of B is 4 times as long as A's. A has an angle of 40° at the peak. How big is B's matching angle?

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7th grade Similar shapes: matching sides and angles worksheet – printable
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About this worksheet

Similar shapes: matching sides and angles. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can match the sides and angles of two similar shapes and find the scale factor from A to B.
  • I can use the scale factor to find a missing side, going from A to B or from B back to A.
  • I can read a statement like “triangle ABC is similar to triangle FDE” to see which sides and corners match, and I know matching angles are equal.

Standard: 7.G.A.1 (partial; similarity proper is 8.G.A.4)

Words to know

similar shapes: Same shape, different size: every side is multiplied by the same number.

matching sides: Sides in the same place on each shape. They are also called corresponding sides.

scale factor from A to B: How many times as long B's side is as A's side: B's side ÷ A's side.

matching angles: Angles in the same place on each shape. In similar shapes they are equal.

similarity statement: A sentence like “ABC is similar to FDE”. Its letters pair up in order.

perimeter: The distance all the way around a shape.

Common mistakes

Your child used the scale factor the wrong way round: divided where the side needed multiplying, or the reverse.

Your child added or took away the gap between two matching sides instead of multiplying. Try it together: if a 2 inch side becomes 6 inches, what does a 5 inch side become?

Your child multiplied by B's whole side instead of by the scale factor.

What to say

Ask: is the second shape bigger or smaller, and should the side come out bigger or smaller?

Ask: how many times as long is B's matching side as A's?

Questions parents ask

What is the most common mistake with similar shapes: matching sides and angles?

Your child used the scale factor the wrong way round: divided where the side needed multiplying, or the reverse.

How can I help my child with similar shapes: matching sides and angles?

Ask: is the second shape bigger or smaller, and should the side come out bigger or smaller?

Are these 7th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

More grade 7 math

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