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Maths — LINES AND ANGLES
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तमसो मा ज्योतिर्गमय · Est. 2025
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Mathematics | Maths Class 9
Mathematics | Maths Class 9 — Complete Notes & Solutions · academia-aeternum.com
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Frequently Asked Questions
A line is a straight, endless path extending in both directions. It is defined by two points and has only length .
An angle is formed when two rays diverge from a common point called the vertex. Angles are measured in degrees .
A ray starts from one point and extends infinitely in one direction, whereas a line segment connects two points and has a definite length .
Collinear points lie on the same line; non-collinear points do not lie on the same line .
Acute (0°–90°), Right (90°), Obtuse (90°–180°), Straight (180°), Reflex (180°–360°), Complete (360°) .
Complementary angles sum to 90°, supplementary angles sum to 180° .
Adjacent: Share a common arm and vertex; Vertically opposite: Formed when two lines intersect, equal in measure; Linear pair: Two adjacent angles whose non-common arms form a line (sum = 180°) .
The sum of the angles in any triangle is \(180^\circ\) .
The sum of interior angles of an n-sided polygon is \((n-2) \times 180^\circ(n-2)\)
A transversal is a line that intersects two or more lines at distinct points .
Corresponding, Alternate Interior, Alternate Exterior, Co-interior (Consecutive Interior) angles .
Corresponding angles are equal; Alternate interior angles are equal; Co-interior angles are supplementary .
The sum of the angles forming a linear pair is \(180^\circ\)
Vertically opposite angles formed by intersecting lines are equal .
Used in engineering, architectural design, navigation, and geographical surveys .