MP Board Book for Class 9th Maths Chapter 6- Lines and Angles

MP Board Book for Class 9th Maths Chapter 6- Lines and Angles

This chapter is based on the MP board syllabus. In this chapter we will learn the basics of lines and angles. Examples and questions are given related to this chapter.

• Lines are made of plenty of points which are straight .
• Angles are the shape formed due two lines. The measurement for the angle is always in degree.  There are different types of angles that are acute angle-less than 90, obtuse angle- more than 90 and less than 180,  right angle- exact 90 degree,straight angle- exact 180 degree, reflex angle- more than 180 degree and less than 360 degree.  
• Portion of a line with two endpoints is called a line segment.

Theorems - 

• If two angles intersect each other then vertically opposite angles are equal. 
• If a transversal intersects two parallel lines such that a pair of alternate angles are equal, then the two lines are parallel.
• If a transversal intersects two parallel lines, then each of the interior angles on the same side of the transversal are supplementary.
• If a transversal intersects two lines such that a pair of interior angles of the transversal is supplementary then the two angles are equal.
• Lines which are parallel to the same line are parallel to each other.
• The sum of the angles of the triangle are 180 degrees.
• If a side of a triangle is produced, then the exterior angle formed  is equal to the sum of two opposite interior angles.