At the college dorm open house, each of the 20 dorm members brings two guests (usually their parents). How many greetings are possible if you do not count dorm members greeting their own guests?

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

Which of these tables represents a non-linear function?

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?