Question

AB and BC are tangents of the circle with the center at D. The measure of ACD = 15°. Which is the measure of ABC?

Answer 1

Anyone

Answer 2

can you post a diagram

Answer 3

http://assets.openstudy.com/updates/attachments/4fa870bae4b059b524f46cba-bdboy0-1336438977297-3878fd319c389fd12f9e5f82b179f44f.gif

Answer 4

ok this is what you should know

tangents from a external point are equal.. so

AB = BC

and tangents and radii intersect at right angles...

so angle BAD = BCD ( both 90)

triangle CDA is isosceles ( since CD and CD are equal radii)

so if ACD = 15 then Angle CAD = 15 ( bass angles of an isosceles triangle)

now you can find angle ADC from angle sum of a triangle

and then you can find angle ABC by angle sum of a quadrilateral

ABC = 360 - 90 - 90 - ADC

hope it helps

Answer 5

Wait so it's 165?