# Basic Concepts Of Geometry Free Doubts and Solutions

### CBSE - IX - Mathematics - Lines and Angles

## A graph may be defined as a set of points connected by lines called edges. Every edge connects a pair of points. Thus a triangle with 3 edge and 3 points. The degree of a point is the number of the edges connected to it. For example, a triangle is a graph with 3 points of degree 2 each. Consider a graph with 12 points. It is possible to reach from any other point through a sequence of edges. The number of edges, e, in the graph must satisfy the condition:- a) 11 ≤ e ≤ 66 b) 11 ≤ e ≤ 65 c) 10 ≤ e ≤ 66 d) 0 ≤ e ≤ 11

**acv27joy**8th October 2018, 10:55 PM

### CBSE - IX - Mathematics - Lines and Angles

## prove that the bisector of two adjacent supplementory angles from a right angle

**sbidipak**27th June 2017, 4:56 PM

### CBSE - IX - Mathematics - Lines and Angles

## Q1. Whatis the history of lines and angles

**vikasg13.hardware**23rd June 2017, 8:38 AM

### CBSE - IX - Mathematics - Lines and Angles

## Two complementary angles are such that two times the measure of one angle is equal to three times the measure of the other. find the measure of the smaller angle.............

**eeshan.nk**18th July 2016, 4:20 PM

### CBSE - IX - Mathematics - Lines and Angles

## An angle is equal to 3 times its complement. Find its measure.

**atharvakute**7th July 2016, 7:56 PM

### CBSE - IX - Mathematics - Lines and Angles

## If angle A and B form a linear pair and angle A - B= 100. Find angle A & B.

**atharvakute**7th July 2016, 7:54 PM

### CBSE - IX - Mathematics - Lines and Angles

## Prove that two distinct lines cannot have more than one point in common.

**kousikroyr20**10th September 2015, 11:42 PM

### CBSE - IX - Mathematics - Lines and Angles

## i am totally confused in proofs please give some easy ways to analize the diagram and to prove it

**sanatkothari99**26th July 2014, 3:45 PM

### CBSE - IX - Mathematics - Lines and Angles

## what are trisect angles

**sanatkothari99**24th July 2014, 4:04 PM

### CBSE - IX - Mathematics - Lines and Angles

## In fig., if y = 20°, prove that the line AOB is a straight line.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In the figure, POR and QOR form a linear pair. If b - a = 60°, find the value of a and b.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## Lines PQ and RS intersect each other at point O. If POR: ROQ= 5:7, find all the remaining angles.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In fig., OP bisects AOC, OQ bisects BOC and OPOQ. Show that points A, O and B are collinear.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In fig, if POR and QOR form a linear pair and a - b = 80° then find the value of a and b.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In fig., find the value of x.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In given figure, OA, OB are opposite rays and

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In fig., two straight lines AB and CD intersect each other at O. If COE = 70o, find the values of a, b and c.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## If two lines are perpendicular to the same line, prove that they are parallel to each other.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In fig., lines l and m intersect each other at O. If x = 40o then, find the value of y, z and w.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## Prove that if two lines intersect, the vertically opposite angles are equal.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In figure, if x : y = 3 : 7, then find the value of x,y,z and w.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In figure, lines AB and CD intersect at O. If AOD : DOC = 4 : 5, then find COB

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## If x + y = s + w, prove that AOB is straight line.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## An angle is of its complement. Find the angles.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In figure, POQ is a line, ray OR is perpendicular to line PQ. OS is another ray lying between rays OP and OR. Prove that ROS = .

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In fig., ray OC stands on the line AB, ray OL and ray OM are angle bisector of AOC and BOC respectively. Prove that LOM = 90o.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## ACB is a straight line. CE and CD are rays making angles with the line such that angle ACE is double the angle DCB and angle ECD is thrice that of angle DCB. Find each of these angles.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## AB and CD intersect at O. If AOD: BOD = 5: 7, find all the angles.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## In the figure, POQ is a line. Ray OR is perpendicular to PQ. OS is another ray lying between rays OP and OR. Prove that ROS =

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## The measure of an angle is twice the measure of its supplementary angle. Find its measure.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## Given that each of the angles AOC and AOB is a right angle. Show that BOC is a straight line.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## Prove that if a ray stands on a line, then the bisectors of the two adjacent angles so formed are perpendicular to each other.

**Topperlearning User**4th June 2014, 1:23 PM

### CBSE - IX - Mathematics - Lines and Angles

## Two angles are adjacent, if they have a common vertex and a common arm. This is the complete definition of adjacent angles. Is this statememt true or false?

**Ayan Biswas**24th May 2014, 2:31 PM

### CBSE - IX - Mathematics - Lines and Angles

## Two angles are adjacent, if they have a common vertex and a common arm. This is the complete definition of adjacent angles. Is this statememt true or false?

**Ayan Biswas**24th May 2014, 2:31 PM

### CBSE - IX - Mathematics - Lines and Angles

## In given figure, if a ray OC stands on line AB such that then show that

**Topperlearning User**3rd December 2013, 2:02 AM