Mathematics Geometry Conceptual 9–10 yrs

Angle Sum Rules

角度和规则

Description

Know that angles at a point sum to 360° (one whole turn), angles on a straight line sum to 180°, and vertically opposite angles are equal; use these facts to find missing angles

Mastery Evidence

✓ State that two angles on a straight line add to 180°
✓ Explain that four right angles at a point make 360°
✓ Identify 270° as three right angles

Assessment Prompt

If three angles meet at a point and two of them are 120° and 95°, can your child work out the third angle — knowing all the angles at a point add up to 360°?