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Lines And Angles

Question
CBSEENMA9002371

In figure, if x + y = w + z, then prove that AOB is a line.


Solution

x + y = w + z    ...(1) | Given
∵ The sum of all the angles round a point is equal to 360°.
therefore x + y + w + z = 3600  
rightwards double arrow x + y + x + y = 3600                       | Using (1)
rightwards double arrow   2(x + y) = 3600
rightwards double arrow space space space space space space space space space space space space space straight x plus straight y equals fraction numerator 360 degree over denominator 2 end fraction
rightwards double arrow           x + y = 1800

∴ AOB is a line.

| If the sum of two adjacent angles is 180°, then the non-common arms of the angles form a line.