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7th grade Find missing angles (straight line, corner, crossing lines) worksheet

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Find missing angles (straight line, corner, crossing lines)

Grade 7 Math Worksheet

NameDate

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

  1. Two bike paths leave a straight trail at the same point near Pia's school. Along the trail the angles are 33°, x and 41°. What is x, in degrees?

  2. Two roads cross by Zee's park. A bike path from the crossing splits one angle into adjacent angles, 38° and 27°. Angle x is across from that whole angle. What is x?

  3. Ari cuts a pizza with two straight cuts that cross. A short cut from the middle splits one angle into 44° and 39°. Angle x is across from that whole angle. What is x?

  4. Luz sticks a paper chain out from the square corner of a window. It splits the corner into complementary angles of 22° and (4x)°. What is x?

  5. Milo's scissors open wide, and the blades cross like an X. Angle x is across from a 137° angle. What kind of angle pair are they?

    • Supplementary angles: they add to 180°
    • Complementary angles: they add to 90°
    • Vertical angles: they are equal

  6. Pia cuts a pizza with two straight cuts that cross in the middle (extra cheese everywhere). Angle x is across from a 76° angle. What kind of angle pair are they?

    • Vertical angles: they are equal
    • Supplementary angles: they add to 180°
    • Complementary angles: they add to 90°

  7. Zee's kite sticks cross like an X. The (x + 25)° angle is across from a 94° angle. Which equation finds x?

    • x + 25 = 94
    • x + 25 + 94 = 360
    • x + 25 + 94 = 90
    • x + 25 + 94 = 180

  8. Bo's tent poles cross at the top like an X. The (4x)° angle is across from a 96° angle. Which equation finds x?

    • 4x + 96 = 90
    • 4x + 96 = 360
    • 4x = 96
    • 4x + 96 = 180

  9. Kira cuts a round pizza into three slices from the center (one slice is clearly the biggest). Two slice angles are 85° and 70°. What is the third angle, x, in degrees?

  10. Luz paints three spokes of a bike wheel bright colors. The painted spokes make angles of 62°, 104° and x around the hub. What is x, in degrees?

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7th grade Find missing angles (straight line, corner, crossing lines) worksheet – printable
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About this worksheet

Find missing angles (straight line, corner, crossing lines). Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can find a missing angle on a straight line (180°), in a square corner (90°), all the way around a point (360°), in a triangle (180°) and where two or three lines cross.
  • I can name a pair of angles: supplementary (add to 180°), complementary (add to 90°), vertical (across, so equal).
  • I can write an equation for an unknown angle, like 3x + 17 + 19 = 90, solve it, and find the angle.

Standard: 7.G.B.5

Words to know

ray: A straight line that starts at a point and goes on in one direction.

straight line: A line with no bend. The angles along it at one point add to 180°.

square corner (right angle): A corner like a page's corner, 90°, marked with a small square.

adjacent angles: Two angles side by side, sharing a corner point and one side.

supplementary angles: Two angles that add to 180°, like the two parts of a straight line.

complementary angles: Two angles that add to 90°, like the two parts of a square corner.

vertical angles: Angles across from each other where two lines cross. They are equal.

unknown angle: An angle we don't know yet, written with x, like (2x + 9)°.

Common mistakes

Your child used 90° for angles on a straight line (180°), or 180° for angles in a square corner (90°).

Your child used 360°, a full turn around a point, for angles that only make a straight line (180°), a square corner (90°) or a triangle (180°), or for two vertical angles, which are simply equal.

Your child mixed up angles across from each other at a crossing (they are equal) with angles side by side on a line (they add to 180°). Try: cross two pencils and point to the angle across from each one.

What to say

Ask: is this a straight line or a square corner?

Ask: do these angles go all the way around the point?

Questions parents ask

What is the most common mistake with find missing angles (straight line, corner, crossing lines)?

Your child used 90° for angles on a straight line (180°), or 180° for angles in a square corner (90°).

How can I help my child with find missing angles (straight line, corner, crossing lines)?

Ask: is this a straight line or a square corner?

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.

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