Question

in a circle of radius 21cm,an arc subtends an angel of 60 degree at the centre then the length of the area is​

Answer 1

I assume we want to know the length of arc, and not the area of sector. ( confusion because in question length of the area is written)

given,

radius r = 21 cm

central angle = 60°

we need to convert it into radian

60° = 60*π/180 radian

= π/3 radian

length of arc = radius x central angle in radian

= 21*π/3

= 7π

= 7*22/7 ( taking π = 22/7)

= 22 cm

if we wanted to know area of sector

area = πr^2*(60/360)

22/7 * 21*21* 1/6

= 21*11

= 231 sqcm