AP EAMCET · Maths · Permutation Combination
How many chords can be drawn through points on a circle?
- A
- B
- C
- D
Answer & Solution
Correct Answer
(B)
Step-by-step Solution
Detailed explanation
Number of points =21 ⇒n=21 A chord connects circle at two points. ⇒r=2 ∴Number of chords from 21 points on a circle =Crn ∴Crn=C221 =21!19!×2! =21×20×19!19!×2×1 =210 ∴ 210 chords can be drawn through 21 points on a circle.
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