Question

Find the distance of the circle circumference with the angle in diagram.

Answer 1

what is the distance of CB on circle?

Answer 2

not the line.

Answer 3

Join the centre and with point C
The angle subtended at the centre would be 2*theta

Answer 4

Arc Length CB = radius x 2theta = 4 * theta ! :)

Answer 5

please explain, i dont get it.

Answer 6

look up for "inscribed angle"

Answer 7

ok, and how did u then get thte arc length?

Answer 8

are we assuming CB is an arc?
if we are, we know that if we were to make a circle with the given dimensions, it would be
C = 2 pi r, and in this case is 2 pi (2) = 4 pi

Notice that the circumference, a distance of 4pi, applies ONLY when the angle theta is 360 degrees (i use degrees cause i hate radians). Now, you can make a proportion.
If 360 degrees gives me 4pi, what angle theta gives me distance CB?

360/4pi = theta/CB

cross multiply and solve for CB. CB = Theta(4pi)/360

Answer 9

use the formula :
arc length = (central angle) x (radius)

Answer 10

so how do u then get to 4 theta from 4pi theta/360?

Answer 11

or would that work with radian instead of degrees?

Answer 12

That only works with radian !

Answer 13

Radius = 2
So Arc Length = 2 theta x 2

Answer 14

can u do the working with radians please

Answer 15

Theta is only a variable here, buddy!
We don't have a value for it.. So how can we put a value ?