My cousin stole my phone and took these pictures xD

Indicate the formula for the following conditions: p^c(n,r)=

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.