Similarly, you can find what is the sum of the angles ,! arranged around a common vertex as in Fig. 23. Continuing one of the parties for a common vertex (. 24 features), we obtain two corners groups: group 1 and a sum equal to two right angles (why?), And the angles of a group of 2, 3, b, the amount of which is equal to two right angles and corners; It means the sum of all angles around a common vertex is 4 right angles. Repeating voprosyChemu equal to the sum of adjacent angles? - The sum of a number of angles, located on one side of a straight line? - The sum of all angles, arranged around a common vertex?