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# Chapter Notes - Lines and Angles Class 7 Notes | EduRev

## Mathematics (Maths) Class 7

Created by: Praveen Kumar

## Class 7 : Chapter Notes - Lines and Angles Class 7 Notes | EduRev

The document Chapter Notes - Lines and Angles Class 7 Notes | EduRev is a part of the Class 7 Course Mathematics (Maths) Class 7.
All you need of Class 7 at this link: Class 7

Angles -An angle is formed when lines or line segments meet.

-The lines that form an angle are called the sides or the arms of the angle.

-The common end point is called the vertex of the angle. -The angle formed by two lines or line segments can be an acute angle, where the measure of the angle is less than 90°.

-The angle formed by two lines or line segments can be a right angle, where the measure of the angle is90°. -The angle formed by two lines or line segments can be an obtuse angle, where the measure of the angle is greater than 90°. -The angle formed by two lines or line segments can be a straight angle, where the measure of the angle is equal to 180°.

-The angle formed by two lines or line segments can be a reflex angle, where the measure of the angle is greater than 180°.

-When the sum of the measures of two angles is 90°, the angles are called complementary angles.

-When the sum of the measures of two angles is 180°, the angles are called supplementary angles.

-Adjacent angles have a common vertex and a common arm, and the non-common arms are on either side of the common arm.

-A linear pair is pair of adjacent angles whose non-common sides are opposite rays.

-Vertically opposite angles are opposite to each other and are equal.

-Adjacent angles have no common interior points.

-The angles in a linear pair are supplementary.

-Angles may have a common vertex and a common arm.

-Two angles are said to be adjacent angles if they have a common side or arm.

-Two adjacent angles can be either supplementary or complementary.

-If two adjacent angles are supplementary, then they form a straight angle, and are also called a linear pair.

-Two angles that are not adjacent but have a common vertex are called vertically opposite angles.

-Vertically opposite angles are equal   Pairs of Lines -Lines that meet at a point are called intersecting lines.

-Lines that meet at a point are called intersecting lines. -Lines that always remain the same distance apart and never meet are called parallel lines. -A line that intersects two or more lines at distinct points is called a transversal.

-When two lines are intersected by a transversal, pairs of corresponding angles, alternate angles and interior angles are formed.

-Angles formed on the same side of a transversal, on the same side of the two lines and at corresponding vertices are called corresponding angles.

-Angles formed on the opposite sides of the transversal at the two distinct points of intersection and between the two lines are called alternate interior angles.

-Angles formed on the opposite sides of the transversal at the two distinct points of intersection but outside the two lines are called alternate exterior angles.

-Angles that have different vertices, lie on the same side of the transversal and are interior angles are called consecutive interior angles or allied or co-interior angles.

-Each pair of interior angles on the same side of the transversal are supplementary, each pair of corresponding angles are equal and each pair of alternate interior angles are equal. -If a transversal cuts two lines such that the pairs of corresponding angles are equal, then the lines are parallel.

-Eight angles are formed when a transversal intersects two lines.

-The angles that lie between the lines are called interior angles.

-The angles that lie on the outer sides of the lines are called exterior angles. ,

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