[Geometry 6] Practice measuring angles

I. METHOD OF MEASURING ANGLE

To measure angle xOy, a protractor is placed so that its center coincides with vertex O of the angle, one side of the angle (such Ox) passes through line 0 of the protractor. Assume that the other side of the angle (ray Oy) passes through line 33. Then we say measurement of angle xOy is 33 degrees.

The measurement of angle xOy is 33 degrees, is denoted by $\widehat {xOy} = {33^0}$ or $\angle xOy = {33^0}$
(Tâm của thước: Center of a protractor)

II. PRACTICE MEASURING ANGLES

Find the measurement of the angles in below figures?

Both angles are $139^0$

You can practice more at website http://www.mathplayground.com/measuringangles.html