Angles on a line and around a pointAngles on a straight line
Name: Date:
Find the angle marked x. The angles on each line add to 180°.
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6 degrees
Angles on a straight line worksheets
Angles sitting side by side along a straight line share what is left of a half turn: together they fill 180°. These free printable worksheets draw angles meeting on a line and mark one with x.
Kid stuck on one? You don’t just get the sheet.
Angles on a straight line
The answer key prints on a separate page.
What's on this sheet
The combined line-and-point sheets ask a child to decide whether the whole is 180° or 360° before subtracting. This one keeps to the straight line, so the total is always 180° and the reading is settled — which lets a child practice the arithmetic of the missing angle without also carrying the choice of which whole applies.
Why this sheet works
When more than one angle is given, the step children skip is adding the known angles before taking them from 180. Add first, then subtract once; the instruction names the total and the figure shows the ruled straight line, so the 180° is read from the picture rather than assumed.
How this one works
One question from this sheet, worked through a step at a time.
Angles on a line: 35°, x, 55°
35° + 55° + x=180°
35° + 55°=90°
180° − 90°=90°
- The angles on a straight line add up to 180°, so all three together make 180°.
- Add the two you are given first: 35 + 55 = 90.
- Then take that from 180°: 180 − 90 = 90. So x = 90°.