Freshman Geometry CHPT.10

In geometry class we have been learning about Chapter 10 (circles). So far I have learned about various segments and formulas. I've learned about radius, chords, and diameters. Formulas I have learned about are C=pi x d / C=2pi x r  <----which are to help find the circumference of a circle. I also learned about different kinds of arcs such as, minor arcs, major arcs, and semicircles. Theorems of chapter 10 are also important to know because it helps you determine how to solve a certain problem about certain circles. Very important! Careers where we can use these certain methods can be astronomy,because of the planets being circular and trying to find the possible circumference of that planet. And last, but not least, a question----->Is the same formula used to find two secants, secant-tangent, and two tangents??