At a business meeting, everyone shook hands with everyone else exactly once. If there were a total of 10 handshakes, how many people were at the meeting.

What are the domain and range of the function f(x)=2^x+1

What is the best approximation for the area of a circle with a radius of 4 m ? use 3.14 to approximate pi

The figure shows triangle def and line segment bc, which is parallel to ef: triangle def has a point b on side de and point c on side df. the line bc is parallel to the line ef. part a: is triangle def similar to triangle dbc? explain using what you know about triangle similarity. part b: which line segment on triangle dbc corresponds to line segment ef? explain your answer. part c: which angle on triangle dbc corresponds to angle f? explain your answer. asap