# Thread: I have more circle questions. 2nd last batch.

1. ## I have more circle questions. 2nd last batch.

use pics for each question. uploaded in order.

20. Given: BC is tangent to circle A;

BD = 17, BC = 15

AC =

A. 16
B. 2
C. 4
D. 8

23. Given: circle P is inscribed in triangle ABC;

AF = 5, CE = 6, BD = 8

The perimeter of the triangle is =

A. 76
B. 4 *15 (15 is squared = *)
C. 19
D. 38

27. Given: AB, AC, and AD are tangent to circle P and circle Q;

AB = 6

Find: AC

A. 6
B. 10
C. 13
D. 80

2 questions left. next post

2. Originally Posted by dgenerationx2
I don't understand this notation of angles.

20. Given: BC is tangent to circle A;

BD = 17, BC = 15

AC =
C. 4

23. Given: circle P is inscribed in triangle ABC;

AF = 5, CE = 6, BD = 8

The perimeter of the triangle is =

D. 38

27. Given: AB, AC, and AD are tangent to circle P and circle Q;

AB = 6

Find: AC

A. 6

2 questions left. next post No threats, please!
to 20:

Use Pythagorean theorem:
$|AC| = \frac12 \cdot |CD| = \frac12 \cdot \sqrt{17^2-15^2}=4$

to 23:

Since |AF| = |AE|, |CE| = |CD|, |BD| = |BF|

all given lengths are used twice. Therefore the circumference is 2(5+6+8) = 38

to 27:

For symmetry reasons |AB| = |AC| = |AD|

Therefore |AC| = 6

3. thanks but still need other one answered.