Book: NCERT - Mathematics
Chapter: 12. Areas Related to Circles
Subject: Maths - Class 10th
Q. No. 4 of Exercise 12.2
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A chord of a circle of radius 10 cm subtends a right angle at the centre. Find the area of the corresponding:
(i) Minor segment
(ii) Major sector (Use π = 3.14)
Let AB be the chord of the circle subtending 90° angle at centre O of the circle.
Area of major sector OADB = (
) * 
r2
= (
) 
r2
= 
* 3.14 * 10 * 10
= 235.5 cm2
Area of minor sector OACB =
* 
r2
= 
* 3.14 * 10 * 10
= 78.5 cm2
Area of ΔOAB =
* OA * OB
= 
* 10 * 10
= 50 cm2
Area of minor segment ACB = Area of minor sector OACB -Area of ΔOAB
= 78.5 - 50
= 28.5 cm2
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