Question

What is the value of x in the figure?

Answer 1

assuming that y and 3y are arc measures, we can say

y + 3y = 180

Answer 2

this is because they form a semi-circle when combined

Answer 3

solve for y and tell me what you get

Answer 4

y=45

Answer 5

good

Answer 6

ok thank you

Answer 7

by the inscribed angle theorem, we can say

2x = 3y

Answer 8

plug in y = 45

2x = 3y

2x = 3*45

and solve for x

Answer 9

2x=135
x=67.5

Answer 10

you nailed it

Answer 11

so what about in this figure?

Answer 12

if 80 is the arc measure, then

2x = 80

Answer 13

so why don't i equal it to 180 this time?

Answer 14

I'm using theorem #3 on this page here

http://www.regentsprep.org/Regents/math/geometry/GP15/CircleAngles.htm

Answer 15

which doesn't involve 180 in this case

Answer 16

ok it's a little confusing but i'm understanding a little at a time. thanks

Answer 17

hopefully it's not all new (and some of it looks familiar)

Answer 18

well because i have to learn this by myself and it's kinda new to me.

Answer 19

oh there's no teacher?

Answer 20

nope :/

Answer 21

oh that sucks, i'm sry to hear that