Question

The length of an arc of a circle is 12cm. The corresponding sector area is 108cm^2. find the radius of the circle?

Answer 1

Need help plz

Answer 2

area of sector = radius x arc length
108 = radius x 12
radius = 108/12
radius = 9

Answer 3

But isn't sector area equation is. =sector area =theta \360 x2pie x r

Answer 4

that is also true but in this case you can only use this one..

Answer 5

Ok thanx

Answer 6

But answer in the book is 18 cm

Answer 7

oh oh oh @Shaaz14 i put the wrong formula the correct one is
area = 1/2 x radius x arc length
108 = 1/2 x radius x 12
radius is therefore 18

Answer 8

One more is that there saying also find the angle sub tended at the centre of the circle by the arc

Answer 9

yeah so you can find the angle using the formula
area = 1/2 x (radius)^2 x angle
108 = 1/2 x (18)^2 x angle
angle at centre = 0.6radians

Answer 10

The answer is coming 38.2*

Answer 11

In the book

Answer 12

my answer is in degrees u can change it to degrrees
0.6 radians = 0.6/pi x 180= 38.2 degrees

Answer 13

I don't get it

Answer 14

pi radians = 180 degrees
taking this ratio u can convert 0.6 radians to degrees