Question

1. If arc AC = 80°, what is the measure of ∠B?
2. If arc ADC = 255°, what is the measure of ∠B?

Answer 1

1. <B is 80 degrees

2. <B is 105 degrees

@lana.831

Answer 2

80 do u know how i got it??

Answer 3

1. 180 or 80? @LizzyLove<3

Answer 4

the choices are 100, 200, 180, 280

Answer 5

oh ok hold on...

Answer 6

Hmmm, maybe @jim_thompson5910 can help??

Answer 7

thanks :)

Answer 8

Arc AC = 80, so central angle AOC is 80 degrees

It turns out that angles AOC and ABC are supplementary, which means they add to 180 degrees

AOC + ABC = 180

80 + ABC = 180

ABC = 180 - 80

ABC = 100

So angle ABC or angle B is 100 degrees

Answer 9

Good Job!! @Luis_Rivera @jim_thompson5910

Answer 10

Arc ADC is 255 degrees, so the minor arc AC must be 360 - 255 = 105 ---> AOC = 105

Then you follow the same steps

AOC + ABC = 180

105 + ABC = 180

ABC = 180-105

ABC = 75

So angle B is now 75 degrees