Question

please answer it right in fig. 1 find the value of x. please do step by step explanation. according to the rule​

Answer 1

Answer:

see this x=20° is it correct

Answer 2

Answer:

We know that a straight line measures 180°

Here AOB is a straight line , which means it measures 180°

Through the figure we observe that ∠AOC + ∠COB = AOB

SO ,

∠AOC + ∠COB  = 180°

It is given that ;

∠AOC = 120°

∠COB = x + 40

If we substitute these values into the equation above :

∠AOC + ∠COB  = 180°   (linear pair)

120°+ x + 40     = 180°

x + 160 = 180                     (here we added 120 and 40)

x = 180-160                 ( transposing a number from one side of = sign to another changes its sign)

x = 20°

Now to find  ∠COB we substitute value of x and solve it .

∠COB = x + 40

∠COB = 20 + 40

∠COB = 60°

Verification :

∠AOC + ∠COB  =  180°

120 + 60 = 180

180°  =  180°

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What is linear pair ?

When a pair of two angles lie on the same line and divide it into 2 angles , but the whole sum is  180° .

As an example the figure in the question itself is an example of linear pair.