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Angles formed by Intersecting Lines
Last updated at July 23, 2025 by Teachoo
Class 7 (Ganita Prakash & Old NCERT)
Chapter 5 Class 7 - Parallel and Intersecting Lines (Ganita Prakash)
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Intersecting Lines
- Parallel and Perpendicular lines
- Between lines
- Parallel and Perpendicular lines in Paper Folding
- Figure it out - Page 113, 114
- Transversals
- Corresponding Angles
- Alternate Angles
- Interior angle on Same side of Transversal
- Drawing Parallel Lines
- Parallel Illusions
- Figure it out - Page 123, 124, 125
Transcript
Angles formed by Intersecting Lines Two lines which meet are called intersecting lines. Here, line 𝑙_1 & 𝑙_2 meet at point O. So, they are intersecting lines. Now, let’s look at the angles Now, these angles have some sort of relation Vertically opposite angles are equal ∴ ∠ 1 = ∠ 3 ∠ 2 = ∠ 4 We can check this by measuring angles using protractor Another relation is of Linear Pair Here, ∠ 4 & ∠ 1 lie on line l2, so they form linear pair ∠ 4 + ∠ 1 = 180° Similarly, ∠ 2 & ∠ 3 lie on other side of line l2, so they form linear pair ∠ 2 + ∠ 3 = 180° We can say the same for line l1 ∠ 1 & ∠ 2 lie on line l1, so they form linear pair ∠ 1 + ∠ 2 = 180° And, ∠ 3 & ∠ 4 lie on other side of line l1, so they form linear pair ∠ 3 + ∠ 4 = 180° We can actually draw lines and Test if this is true using a Protractor Let’s do it…
