1. 
Quadrilateral PQRS is circumscribed about a circle. If AQ = 10, QR = 15, and DS = 12, find the length of _{}.


2. 
_{}P and _{}Q have radii 25 cm and 10 cm. _{} is the common internal tangent to _{}P and _{}Q. If RC:CS = 5:2 and PQ = 37 cm, find PC.



4. 
_{} is tangent to circle O at point P. _{} intersects the circle at B. If m_{}A = 40, then m_{}APB = ______.


5. 
_{} and _{} are tangent to _{}C. If AB = (2x  8) and AD = (11x  80), find the value of x 

6. 
_{} and _{} are tangents to circle O. If OA = 24 cm, OP = 12 cm, and m_{}PAQ = 60, find the area of quadrilateral OPAQ. 
