Question

mAB=120 degrees and AC is the diameter of this circle. What is the degree measure of 13 years ago

Answer 1

What is the measure of arc BC?

Answer 2

60?

Answer 3

So remember...the inscribed angle is 1/2 its arc

Answer 4

half of 120 ? or..

Answer 5

What is the arc of angle BDC?

Answer 6

how do you find that ?

Answer 7

Do you see how the sides of angle A intersect the circle and form arc BC?

Answer 8

yes

Answer 9

BC is called the are intercepted by angle A.

Answer 10

Angle A is an inscribed angle because its vertex is on the circle.

Answer 11

oh okay got you!

Answer 12

So what is the arc of angle BDC?

Answer 13

BC is the arc

Answer 14

and what is its measure?

Answer 15

60 ?

Answer 16

And is angle BDC an inscribed angle?

Answer 17

yes

Answer 18

Well then...its measure is 1/2 of its arc.

Answer 19

so half of 60?

Answer 20

yep

Answer 21

is 30

Answer 22

Way to go!!

Answer 23

so the degree measure of <BDC is 30

Answer 24

yes

Answer 25

ok :)