NumihanaTwo angles on a straight line total 180°. One is 120°. What is the other angle?
Answer: ________________
LEARN, PRINT & PRACTISE
Angles on a straight line.
Find an angle using a straight-line total of 180 degrees.
Numihana · England Year 5
Angles on a straight line
Practice sheet
Name: ______________
Date: ______________
Find an angle using a straight-line total of 180 degrees.
Two angles on a straight line total 180°. One is 100°. What is the other angle?
Answer: ________________
Two angles on a straight line total 180°. One is 120°. What is the other angle?
Answer: ________________
Two angles on a straight line total 180°. One is 110°. What is the other angle?
Answer: ________________
Two angles on a straight line total 180°. One is 160°. What is the other angle?
Answer: ________________
Two angles on a straight line total 180°. One is 90°. What is the other angle?
Answer: ________________
Numihana · England Year 5
Angles on a straight line
Answer key
Name: ______________
Date: ______________
Find an angle using a straight-line total of 180 degrees.
Two angles on a straight line total 180°. One is 120°. What is the other angle?
Answer: 60
Two angles on a straight line total 180°. One is 100°. What is the other angle?
Answer: 80
Two angles on a straight line total 180°. One is 120°. What is the other angle?
Answer: 60
Two angles on a straight line total 180°. One is 110°. What is the other angle?
Answer: 70
Two angles on a straight line total 180°. One is 160°. What is the other angle?
Answer: 20
Two angles on a straight line total 180°. One is 90°. What is the other angle?
Answer: 90
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The skill behind this activity
Find an angle using a straight-line total of 180 degrees.
Department for Education: mathematics programmes of study ↗
Year 5 → Geometry → Properties of shapes · Selected statutory skill. Pack 2.2.0 · source checked 2026-10-12.
For teachers and parents
Compare an angle with a right angle, or use the fact that angles on a straight line total 180 degrees.
A common slip
An angle depends on the amount of turn, not the length of its arms.
Worked example
Two angles on a straight line total 180°. One is 140°. What is the other angle?
Answer: 40
Compare an angle with a right angle, or use the fact that angles on a straight line total 180 degrees.