Question

What is the measure of AB?

Answer 1

Here you have two chords that intersect inside the circle. Do you know the relationship between AY, YB, CY and YD?

Answer 2

i know you need to multiply CY and YD. which is 72 but i dont know what is next.

Answer 3

CY(YD)=AY(YB)
6(12)+AY(9)

Answer 4

72 + AY(9)

Answer 5

Find AY

Answer 6

how ?

Answer 7

Can you solve this equation: 4x = 12

Answer 8

x=3

Answer 9

How about this one: 9x=72

Answer 10

x=8

Answer 11

How about this one: 72= x(9)

Answer 12

its the same thing isnt it ?

Answer 13

And this one 72=AY(9)

Answer 14

you just changed the x

Answer 15

So AY is 9. Now find AB

Answer 16

18?

Answer 17

No. I mean 8. AY is 8

Answer 18

CY * YD = AY * YB
Now substitue every know value intot he equation:
6 * 12 = AY * 9
72 = 9(AY)
AY = 72/9
AY = 8

Answer 19

And AB is 8 + 9 or 17

Answer 20

Now that you know that AY = 8, AB = AY + YB, and you know both AY and YB, so just add them up.

Answer 21

so, AB is 17

Answer 22

correct

Answer 23

thanks :)