Tick the correct answer in the following: If the perimeter and the area of a circle are numerically equal, then the radius of the circle is
(A) 2 units (D) π units
(C) 4 units (D) 7 units.
A chord of circle of radius 10 cm subtends a right angle at the centre. Find the area of the corresponding :
(i) Minor segment
(ii) Major sector.
Here, we have
r = 10 cm, and ө = 90°
Area of sector (OAPBO)
Area of AOB
Now,
(i) Let APB A is the given minor segment, then Area of minor segment (APBA)
= Area of sector (OAPBO) - area of ∆ (AOB)
= 78.5 cm2 - 50 cm2
= 28.5 cm2.
(ii) Area of major sector
= Area of circle Area of sector OAPBO
= (πr2 - 78.5) cm2
= (3.14 × 10 × 10 - 78.5) cm2
= (314 - 78.5) cm2 = 235.5 cm2
In a circle of radius 21 cm, an arc subtends an angle of 60° at the centre. Find :
(i) the length of the arc
(ii) area of the sector formed by the arc
(iii) area of the segment formed by the corresponding chord.