Because the 3 interior angles of any triangle add up to 180 degrees.
Get a...PROTRACTOR!
The sum of all the interior angles of any trapezoid is 360 degrees.
with a protractor
Using a protractor will help but in general vertical angles on a straight line add up to 180 degrees.
You could estimate. If it is not right, it is between 90 degrees and 0 degrees. If it is between right and straight angles, it would be between 90 degrees and 180 degrees. You can sort of figure out roughly where each and measurement was.
the answer is cone
An isosceles triangle.
Without knowing any other property of that triangle, you can't.
If all of the angles add to 180 degrees the figure is a triangle. * * * * * That is if they form a plane figure. Angles that add to 1890 degrees are called supplementary angles.
Measuring tools: Ruler or Protractor .
No, only their positions will change.
If, by quadrangle, you mean quadrilateral (four sided figure), than the angles add to 360 degrees. You can figure out the degree measure for any sided figure by simply letting the number of sides equal the variable n, and using the equation 180(n-2) (one hundred eighty times n minus 2). This works for any figure.