Theory:

Angle:
When two lines meet, they always meet at a certain angle. An angle is specified using a number followed by a \((^\circ)\) symbol like \(15^\circ\), \(120^\circ\), \(180^\circ\), and so on.
Example:
fig_1.png
 
In the figure given above, \(\overline{CD}\) meets \(\overline{CB}\) at \(90^\circ\)
An angle can be constructed by using a protractor.
  
Let us see how to construct a an using a protractor.
  
Step 1: Draw a line segment \(PA\).
 
figure_1.png

Step 2: Place the protractor on the line segment \(PA\) by taking the midpoint of the protractor at point \(P\), as shown in the figure.
 
figure_2.png

Step 3: On \(PA\) from the right, start counting from \(0°\) in the ascending order (counter-clockwise direction and finally mark a point \(Q\) using a sharp pencil at the point showing \(60°\) on the semi-circular edge of the protractor.
 
figure_3.png
 
Step 4: Remove the protractor and join \(PQ\).
 
figure_4.png
 
We get the required angle, \(∠APQ =\) \(60°\).