In the course of an afternoon walk, Mr. Hooper met, consecutively, 10 friends, and every one of them was
wearing a hat. They greeted each other by tipping their
hats. Il people wearing
1. How many times was that done?
2. How many times would those hats have been lifted
if their owners had met simultaneously?
a hat.

What is the volume of this square pyramid?

Identify the converse of the following conditional: if a point is in the first quadrant, then its coordinates are positive. if the coordinates of a point are not positive, then the point is not in the first quadrant. if the coordinates of a point are positive, then the point is in the first quadrant. if a point is in the first quadrant, then its coordinates are positive. if a point is not in the first quadrant, then the coordinates of the point are not positive.

Based on the figures as marked, /\rqs = —