Sum of the angles around a point — lesson. Mathematics State Board, Class 7.

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எங்கள் ஆசிரியர்களுடன் 1-ஆன்-1 ஆலோசனை நேரத்தைப் பெறுங்கள். டாப்பர் ஆவதற்கு நாங்கள் பயிற்சி அளிப்போம்

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Linear pair:

Linear pair of angles should add up to

$180°$ .

If the given two adjacent angles does not make the

$180°$ , then it is not a linear pair.

We studied that the sum of all the angles formed at a point on a straight line is

$180°$ .

Think what would be the angle if many rays arises from a single point!

All the rays are starting from a single point. So the sum of the angles around a point will be

$360°$ .

Now we understand this with some example.

Observe the below figure. Here

$AB$ is a straight line. And

$OC$ is a ray meeting

$AB$ at

$O$ . It is evident that

$∠ AOC$ and

$∠ BOC$ is a linear pairs, so it makes the angles of

$180°$ .

Also the another ray

$OD$ meeting

$AB$ at

$O$ . Then

$∠ AOD$ and

$∠ BOD$ is a linear, which makes

$180°$ .

We can observe that all the angles

$∠ AOC$ ,

$∠ BOC$ ,

$∠ AOD$ and

$∠ BOD$ are originated at the point of

$O$ .

Therefore,

$(∠ AOC + ∠ BOC) + (∠ AOD + ∠ BOD) = 180 ° + 180 ° = 360 °$ .

Hence, it is clear that the sum of the angles at a point will be

$360°$ .

Did you find an error?

3. Sum of the angles around a point