Question

solve it proper solution​

Answer 1

Answer:

That all right angles are equal to one another. That if a straight line falling on two straight lines makes the interior angles on the same side less than two right angles, the straight lines, if produced indefinitely, will meet on that side on which the angles are less that two right angles. *

Step-by-step explanation:

it is a postulate learn it by heart

Answer 2

Answer:

Do you mean square ?

A square have all sides right angles with a total of 4 sides,

A square = 4 × 90 = 360°