Question

In the figure below, CE and AB are parallel and CE is the bisector of angle ACD. If angle ACD measures 110 degrees, what is the measure of arc BC?

Answer 1

(you don't have to give me a straight answer. I would rather be walked through it because I need help on it.)

Answer 2

55 degrees.

Answer 3

arcBC should be 2 times the measure of angleA i think

Answer 4

Angles ACE and ECD are same (bisector). The total is 110. So, each is 55 degrees.

Answer 5

Because AB and CE are parallel, angle BAC must equal angle ACE = 55 degrees.

Answer 6

but the arc of BC is what I'm trying to find, how would I know the measure of that arc?

Answer 7

(this is where I always get confused)

Answer 8

there is a thrm which pretty much goes like this:

Answer 9

the arcLength is either the central angle; or twice the angle thats on the rim of the circle

Answer 10

since in your picture: A is the angle measureing arcBC, we need to determine A and double it

Answer 11

oh wait....

Answer 12

the other guy said A would equal 55 since AB is parallel to CE

Answer 13

right, A = 55

Answer 14

so 110

Answer 15

is A doubled

Answer 16

correct, arcBC = 110

Answer 17

Oh, thank you !!

Answer 18

yep