Lines and angles class 7 mathematics
- 3. LINE : A straight path extending in both directions with no end points. LINE SEGMENT: A part of a line that includes two points, called endpoints, and all the points between them. RAY:A part of a line, with one endpoint, that continues without end in one direction.
- 4. An angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle. The magnitude of the angle is the amount of rotation that separates the two rays, and can be measured by considering the length of circular arc swept out when one ray is rotated about the vertex to coincide with the other.
- 5. Acute angle Right angle Obtuse angle Straight angle Complementary angle Supplementary angle Adjacent angle Linear pair of angles Vertically opposite angles
- 6. The measure of an angle with a measure between 00 and 90o or with less than 90o radians
- 8. An angle formed by the perpendicular intersection of two straight lines, an angle of 90o.
- 10. An angle measures greater than 90 degrees but less than 180 degrees.
- 12. A straight angle changes the direction to point the opposite way. It looks like a straight line. It measures 180o (half a revolution or two right angles.)
- 14. When the sum of the measures of two angles is 900 the angles are called complementary angles.
- 15. When the sum of the measures of two angles is 1800 the angles are called supplementary angles.
- 16. In geometry, adjacent angles are angles that have a common ray coming out of the vertex going between two other rays. In other words, they are angles that are side by side, or adjacent.
- 17. A pair of adjacent angles formed by intersecting lines. Linear pair of angles are supplementary.
- 18. A pair of angles is said to be vertical if the angles are formed from two intersecting lines and the angles are not adjacent. They all share a vertex. Such angles are equal in measure and can be described as congruent.