00:01
In the diagram shown, bc is a tangent circle a at point c.
00:05
If a .b equal to 17, b .c equal to 15, then which of the following is the length of the radius of circle a is the question? so i've joined the point a .c here to keep the angle.
00:14
The angle between the radius and the tangent is always equal to 90.
00:18
Therefore, a .b .c is a right angle triangle.
00:21
A .b.
00:21
Squared should be equal to a .c.
00:23
Square plus b .c.
00:23
Square according to the pythagraph's theorem, which would then mean 17 squared should be equal to ac squared plus 15 squared.
00:30
We can recalculate ac squared by saying 17 squared minus 15 squared, then you can take the square root and find out ac should be equal to 8.
00:38
So for the first problem, the answer is ac equals to 8, which is option 2.
00:44
In the second case, the circle who is a diameter of 16, and a point c is located outside the circle so that lies 12 units from the circle center.
00:52
Then they're asking a question, what is the length of the segment drawn from c? and express your answer in simple astratical form.
00:57
In this case, ac equal to 12, a, a, b equals to 8, and ac squared equals to a, b squared plus b .c squared plus b .c.
01:05
Square plus b .c.
01:05
Quared plus a, it's again the same logic from the previous problem.
01:07
B .c.
01:08
Equals to 12 squared minus 8 squared, which would then mean bc equal to 4 root 5...