SOLUTION: If AC = 25 mm and AB = 15 mm, calculate the length of AD. AC is also line ADC. AB is on the outside of the circle and AD is inside. A.16 mm B.15 mm C.9 mm D.14 mm

Algebra ->  Circles -> SOLUTION: If AC = 25 mm and AB = 15 mm, calculate the length of AD. AC is also line ADC. AB is on the outside of the circle and AD is inside. A.16 mm B.15 mm C.9 mm D.14 mm      Log On


   

Question 1152375: If AC = 25 mm and AB = 15 mm, calculate the length of AD.
AC is also line ADC. AB is on the outside of the circle and AD is inside.
A.16 mm

B.15 mm

C.9 mm

D.14 mm
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

The square of the length of the tangent equals the product of the length of the secant and its exterior secant.
Therefore,
%28AB%29%5E2=+%28AC%29%28AD%29
If AC+=+25mm and AB+=+15mm, we have:
15%5E2=+%2825%29%28AD%29
225+=+25%28AD%29
AD+=+9+mm

answer: C.9mm