Using only a ruler, draw an acute angle, a right angle and an obtuse angle in your notebook and name them.

Write the name of the vertex and the arms of $\angle \mathrm{ABC}$, given in the figure below.

How many angles are formed in the figure given below? Name them.

Note: This question given in the book seems to have errors and the modified question should be as given below.

How many angles are formed the figure given below? Name them.

How many angles are formed in the figure given below? Name them.

How many angles are formed in the figure given below? Name them.

Name all the angles formed in this figure.

In the figure, name the points which are in the interior of $\angle PQR$

Using a pair of compasses construct the following angle: $90°$