Math · Geometry Lab

Angles and Lines

When two lines meet, they make an angle — and we measure how open it is in degrees.
📐Four Kinds of Angles
🤏Acute
40°
Less than 90°Small & "cute" — a narrow corner.
📏Right
90°
Exactly 90°A perfect square corner. 🔲
📂Obtuse
130°
More than 90°Wide & leaning back open.
Straight
180°
Exactly 180°A flat, straight line. ➡️
🛤️How Two Lines Can Travel
🚂Parallel Lines
same gap → never touch ✗
They run side-by-side forever and never cross — always the same distance apart.
Perpendicular Lines
90° a perfect cross +
They cross to make a right angle (90°) — like streets at a four-way intersection. 🚦
🔍The Parts of an Angle
angle vertex ray → ray →
📐 Every angle is built from these:
Vertex — the point where the two rays meet.
Rays — the two straight arms going out forever.
Degrees — how far open the angle is, from 0° to 360°.
🔑Key Terms
📐Angle Two rays meeting at a point, measured in degrees.
🤏Acute Angle Measures LESS than 90° — small and narrow.
📂Obtuse Angle More than 90° but less than 180° — wide open.
📏Right Angle Exactly 90° — a perfect square corner.
Straight Angle Exactly 180° — a perfectly flat, straight line.
🚂Parallel Lines Never cross; stay the same distance apart.
Perpendicular Lines Cross to form a right (90°) angle.
Remember: angles are measured in degrees — a right angle is exactly 90°, acute angles are smaller, and obtuse angles are bigger!
✏️ Math Anchor Chart · Angles and Lines
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