SOLUTION: the segments GA and BG are tangent to a circle at A and B, and AGB is a 48 degree angle. Given that GA = 12 cm, find the distance from G to the nearest point on the circle.

Algebra ->  Circles -> SOLUTION: the segments GA and BG are tangent to a circle at A and B, and AGB is a 48 degree angle. Given that GA = 12 cm, find the distance from G to the nearest point on the circle.       Log On


   



Question 149128: the segments GA and BG are tangent to a circle at A and B, and AGB is a 48 degree angle. Given that GA = 12 cm, find the distance from G to the nearest point on the circle.
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
the segments GA and BG are tangent to a circle at A and B, and AGB is a 48 degree angle. Given that GA = 12 cm, find the distance from G to the nearest point on the circle.

 

Label the center of the circle O. and 
draw radii to A and B. Let the radius be r



Next draw OG which bisects the 48° angle G into
two 24° angles. Let P be the point where OG intersects
the circle.  P is the nearest point on the circle to G, 
so GP is the distance we're looking for.

Plan: Calculate the radius OA and the hypotenuse OG using the 
upper right triangle using trig ratios. Then calculate OG. Then 
since OP is also a radius, we will subtract the radius OP from 
OG and get GP.
 


In the right triangle AOG, radius AO is the side opposite
angle AGO which is 24°.  GA is the side adjacent to angle AGO.

So we use 

tangent=%28opposite%29%2F%28adjacent%29

tan%2824%29=r%2F%28GA%29

tan%2824%29=r%2F12

Put 1 under the tan%2824%29

tan%2824%29%2F1=r%2F12

Cross-multiply:

r=12tan%2824%29

Next we calculate OG:

---
OG is the hypotenuse, GA is the opposite side of 24°

So we use 

cosine=%28adjacent%29%2F%28hypotenuse%29

cos%2824%29=GA%2FOG%29

cos%2824%29=12%2FOG

Put 1 under the cos%2824%29

cos%2824%29%2F1=12%2FOG

Cross-multiply:

OG=12cos%2824%29

So now we can find GP by

subtraction, since OP = r = 12tan(24)

GP = OG - OP = 12cos%2824%29-12tan%2824%29=5.61981268cm

Edwin