Lines and Angles-Important Questions

1.  In the given figure, AOC is a line, find x.

2.  In the given figure, intersect at O.

      (a)   Determine y, when x = 60°.

      (b)   Determine x, when y = 40°.

3.  In the given figure, lines Ab, CD and EF intersect at O.

      Find the measure of ∠AOC, ∠COF.

4.  The exterior angles obtained on producing the base of a triangle both ways are 100° and 120°. Find all the angles.

5.  ΔABC is right angled at A and AL ┴ BC. Prove that ∠BAL = ∠ACD.

6.  If two parallel lines are intersected by a transversal, prove that the bisectors of the two pairs of interior angles enclose a rectangle.

7.  The angles of a triangle are arranged in ascending order of magnitude. If the difference between two consecutive angles is 10°, find all the three angles.

8.  In the given figure, POQ is a line. Ray is another ray lying between rays and Prove that

9.  Can a triangle have two obtuse angles? Give reason for your answer.

10.  How many triangles can be drawn having its angles as 45°, 64° and 72°? Give reason for your answer.