How do I solve 6 a & b and #7 a?

Both the red and blue line segments stretch from the center of the circle to a point on the circle. the length of the blue segment is 5. how long is the red line segment?

Which statement is true? n is a point of tangency on circle p. pt is a secant of circle p. is a secant of circle p. vu is a tangent of circle p.

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible