| --- |
| source: ncert |
| topic: geometry |
| class_level: class_7 |
| chapter: ch5 |
| difficulty: beginner |
| --- |
| |
| Class 7 | Ch5: Lines and Angles |
| Complementary=90° total. Supplementary=180° total. Linear pair=180°. Vertically opposite=EQUAL. |
| Parallel lines + transversal: 8 angles formed. |
| Corresponding angles: same position=EQUAL (F-shape). |
| Alternate interior angles: between lines, alternate sides=EQUAL (Z-shape). |
| Co-interior angles: between lines, same side=SUPPLEMENTARY=180° (C-shape). |
| Alternate exterior angles: outside, alternate sides=EQUAL. |
| Converse: if corresponding/alternate angles equal → lines parallel. |
| Example: angle=65°. Corresponding=65°. Alternate interior=65°. Co-interior=115°. |
| Two supplementary angles, one=3 times other: x+3x=180 → x=45°, angles=45° and 135°. |
| Co-interior angles SUPPLEMENTARY not equal. Vertically opposite ALWAYS equal. |
