AB and AD are tangents of the circle with the center at C. The measure of BDC = 45o, and the circle has a diameter of 4. Which is the length of AB?

Question

ganeshie8 · Answer

draw it out

anonymous · Answer

attachment

anonymous · Answer

so how do  you do that?

ganeshie8 · Answer

use this : base angles of isosceles triangle congruent

anonymous · Answer

what is that?

ganeshie8 · Answer

lookup isosceles triangle and get some familiarity with that first, then oly you can solve this

phi · Answer

phi · Answer

notice line segment CD and line segment  CB are both a radius=  1/2 the diameter
= 1/2 * 4 = 2

phi · Answer

angle CDB is 45º.  what is angle CBD ?

anonymous · Answer

45 as well

phi · Answer

if you have a triangle with 45, 45,   what is the 3rd angle BCD ?

phi · Answer

knowing all 3 angles add up to 180

phi · Answer

next, what is the angle CDA  formed by the tangent line ?