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8th grade Is it a right triangle? (the converse) worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

Level: Building Confidence · On Level · Challenge Me

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Is it a right triangle? (the converse)

Grade 8 Math Worksheet - Building Confidence

NameDate

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

  1. Bo cuts a paper triangle with sides of 9, 4 and 8 cm. What do the squares on the two shorter sides add up to, in square cm?

  2. Jun draws a triangle with sides of 7, 9 and 5 cm on a poster. What do the squares on the two shorter sides add up to, in square cm?

  3. Kira's class ropes off a triangle-shaped flower bed with sides of 11, 7 and 8 feet. What do the squares on the two shorter sides add up to, in square feet?

  4. Milo glues three paper squares onto the sides of a triangle. Their areas are 20, 45 and 65 square cm. Is the triangle a right triangle?

    • It is not a right triangle: the two smaller squares do not add up to the biggest one.
    • You cannot tell without measuring the angles.
    • It is a right triangle: the two smaller squares add up to the biggest one.
    • It is a right triangle, because one square is much bigger than the other two.

  5. Pia builds squares of tiles on the sides of a triangle: 64, 24 and 40 square inches. Is the triangle a right triangle?

    • You cannot tell without measuring the angles.
    • It is a right triangle, because one square is much bigger than the other two.
    • It is a right triangle: the two smaller squares add up to the biggest one.
    • It is not a right triangle: the two smaller squares do not add up to the biggest one.

  6. Ren's math book shows squares of 36, 50 and 90 square cm on the sides of a triangle. Is the triangle a right triangle?

    • It is a right triangle: the two smaller squares add up to the biggest one.
    • You cannot tell without measuring the angles.
    • It is a right triangle, because one square is much bigger than the other two.
    • It is not a right triangle: the two smaller squares do not add up to the biggest one.

  7. Tala lists the sides of a triangle as 9, 4 and 7 cm. To test for a right angle, which square must the other two add up to?

    • The square on the side of 9 cm
    • The square on the side of 4 cm
    • The square on the side of 7 cm

  8. Zee's worksheet gives a triangle's sides as 12, 15 and 10 inches. To test for a right angle, which square must the other two add up to?

    • The square on the side of 12 inches
    • The square on the side of 15 inches
    • The square on the side of 10 inches

  9. A triangle on Ari's park map has sides of 6, 14 and 11 feet. To test for a right angle, which square must the other two add up to?

    • The square on the side of 6 feet
    • The square on the side of 11 feet
    • The square on the side of 14 feet

  10. Bo cuts a triangle with sides of 18, 13 and 8 cm. To test for a right angle, which square must the other two add up to?

    • The square on the side of 8 cm
    • The square on the side of 13 cm
    • The square on the side of 18 cm
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8th grade Is it a right triangle? (the converse) worksheet – printable
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About this worksheet

Is it a right triangle? (the converse). Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can find the longest side, wherever it is listed, and square every side.
  • I can decide whether a triangle has a right angle: the two smaller squares must add up to exactly the biggest.
  • I can say where the right angle is (across from the longest side) and check a square corner in a real frame.

Standard: 8.G.B.6 (the converse)

Words to know

right triangle: A triangle with one square corner.

converse: The theorem turned around: if the squares add up, there is a right angle.

longest side: The side whose square must equal the other two squares together.

square corner: A right angle, like the corner of a door frame.

near miss: Squares that come close but are not equal: not a right triangle.

Common mistakes

Your child added the side lengths instead of their squares. The test for a right triangle adds the squares on the two shorter sides. Try it on a 3, 4, 5 triangle: 9 + 16 = 25.

Your child squared and added, but used the longest side. The test adds the squares on the two shorter sides and compares them with the square on the longest side. Point to the longest side together first.

Your child said the triangle is not right when the two smaller squares add up exactly to the biggest. Equal sums always mean a right angle. Add the two smaller squares together and compare.

Questions parents ask

What is the most common mistake with is it a right triangle? (the converse)?

Your child added the side lengths instead of their squares. The test for a right triangle adds the squares on the two shorter sides. Try it on a 3, 4, 5 triangle: 9 + 16 = 25.

Are these 8th 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 8 math

See all grade 8 math

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