We will learn how to construction of an angle using a protractor.
Let us draw an angle whose measure is 60°. Use a ruler to draw YZ.
Now, place the protractor over YZ such that the baseline of the protractor coincides with YZ and midpoint of the baseline coincides with point Y.
Mark a point X where you find 60 on the protractor. Now, join X and Y with the help of a ruler. We ∠XYZ = 60°.
Let us draw an angle EFG measuring 120°. Draw a ray EF. Place the protractor over EF such that the baseline of the protractor coincides with EF and the midpoint of the baseline coincides with point F. Read markings on the outer semicircle of the protractor and mark point G on 120°.
Join F and G with the help of a ruler. We have ∠EFG = 120°.