how many chords can be drawn through 21 points on a circle ?
Answers
hey mate ur ans is in the given attachment
Answer:
210 chords.
Step-by-step explanation:
Firstly, Number of points = 21
Hence, n=21
A chord connects circle at exactly 2 points
Hence, r = 2
Now, the Number of Chords from 21 points = nCr
= 21C2
= 21!/2!(21-2)
= 21!/2! 19!
= 21×20×19!/(2×1)19!
= 21×20/2
= 210 chords.
Therefore, 210 chords can be drawn through 21 points on a circle.
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i hope it will helps you friend