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Angles on a Straight Line Worksheet – Grade 5

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📄 Angles on a Straight Line Worksheet – Grade 5

Help students understand straight angles and use the 180° rule to calculate missing angle measures through focused geometry practice.

Angles on a Straight Line: Interactive Check

Use the straight-angle rule to solve these Grade 5 questions. Angles forming a straight angle total 180°.

Question 1: Two adjacent angles on a straight line measure 70° and x°. Find x.

Reveal answer and explanation

Answer: 110°.
Explanation: x = 180° − 70° = 110°.

Question 2: Three adjacent angles lie along a straight line. Their measures are 45°, 65°, and x°. Find x.

Reveal answer and explanation

Answer: 70°.
Explanation: x = 180° − 45° − 65° = 70°.

Question 3: Do any two adjacent angles always add up to 180°?

Reveal answer and explanation

Answer: No.
Explanation: Adjacent angles add to 180° when they form a straight angle.

Question 4: An angle on a straight line is 128°. What is the other angle beside it?

Reveal answer and explanation

Answer: 52°.
Explanation: 180° − 128° = 52°.

Question 5: Two angles on a straight line are x° and 39°. Find x.

Reveal answer and explanation

Answer: 141°.
Explanation: x = 180° − 39° = 141°.