Grade 7 · Math

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 - Challenge Me

NameDate

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

On Jun's trail map, a side path leaves a straight trail. The angles on each side of the path are 52° and (2x + 14)°. What is x?
Luz tapes a streamer out from the square corner of the art table. It splits the corner into 19° and (3x + 17)°. What is x?
Noah's kite sticks cross, and the kite swoops like a happy bird. The (2x + 9)° angle is across from the 67° angle. What is x?
Ren cuts a pizza with three straight cuts through the middle, making six slices. Two angles are marked 52° and 67°, as the sketch shows. What is angle x, in degrees?
Three straight streets meet at one point on Tala's town map. Two angles are marked 48° and 73°, as the sketch shows. What is angle x, in degrees?
Bo's desk lamp arm leans on the flat desk. The angles on each side of the arm are (3x)° and (2x + 15)°. How big is the (2x + 15)° angle, in degrees?
7.
Milo stitches two lines out from the square corner of a quilt square. They split the corner into 21°, (2x)° and 37°. Which equation finds x?
- 2x = 21 + 37
- 21 + 2x + 37 = 180
- 21 + 2x + 37 = 90
- 21 + 2x + 37 = 360
Pia cuts a cake into four pieces from the center. The angles at the center are 100°, 110°, x° and (2x)°. What is x?
Four spokes on Tala's bike wheel are painted. The angles between them around the hub are 75°, 45°, x° and (2x)°. What is x?
The front of Zee's tent is a triangle, with one flap that never stays shut. Its angles are (2x)°, (3x + 10)° and 50°. What is x?

7th grade Find missing angles (straight line, corner, crossing lines) worksheet – printable — Print: 1 2 3 4 5 6

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.

More grade 7 math

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