How many right angles make a complete angle?

If $ABC$ is a straight line then value of $x$, in the given diagram will be 

The wheels of a car are of diameter $80 \mathrm{c}\mathrm{m}$ each. How many complete revolutions does each wheel make in 10 minutes when the car is traveling at a speed of $66 \mathrm{k}\mathrm{m}$ per hour? $\left(\mathrm{use} \pi =\frac{22}{7}\right)$

In the given figure, $AB\parallel CD, \angle ABO=40°$ and $\angle CDO=35°$. Then the value of $x$ will be

Only one circle can be drawn through three non collinear points.

Which angle has a large measure? First estimate and then measure the angle $\mathrm{A}$ and angle $\mathrm{B}$.

Measure $\angle ABC$ given in the given figure and construct an angle $DEF$ equal to $\angle ABC$.

From these two angles which has larger measure? Estimate and then confirm by measuring them.

How many degrees are there in the angle between the hour hand and the minute hand of a clock, when it is

$3$ $o\text{'}$clock?

Match the following:

What is the number of obtuse angles in the given figure?