yes you can
There are 4 angles in a trapezoid that add up to 360 degrees.
it is a trapozoid
no
Yes.
12
It is impossible to have a triangle with 3 right angles. It is possible to draw a triangle with three right angles on the surface of a sphere: www.metacafe.com/watch/769025/270_degree_triangle_yes_3_right_angles
No, because then it would be a rectangle.
if i put three points on the common arm ,then they are common points for both the two angles
Yes, but the 4 interior angles of a trapezoid must add up to 360 degrees.
The sum of all four angles is 360 degrees. If three of the angles were right angles then the fourth would have to be a right angle. You would then have a rectangle or a square, but not a trapezium.
Yes.
Yes, as long as they all add up to 180 degrees. A triangle cannot have 2 right angles. A triangle with three different angles is called a scalene triangle.