Construct $\stackrel{-}{\mathrm{PQ}}$ of length $8$$\mathrm{cm}$. Cut off $\stackrel{-}{\mathrm{PM}}$ of length $3.6$ $\mathrm{cm}$ from it. Measure the length of $\stackrel{-}{\mathrm{MQ}}$. Verify that length of $\stackrel{-}{\mathrm{PQ}}$ - length of $\stackrel{-}{\mathrm{PM}}$ $=$ length of $\stackrel{-}{\mathrm{MQ}}$.

Draw $$$\overline{\mathrm{AB}}$, take a point $\mathrm{C}$ on it and draw a perpendicular $\overline{\mathrm{CD}}$ on $\overline{\mathrm{AB}}$ using a set -square and a ruler. How many such lines can be drawn?

Draw $\overline{\mathrm{XY}}$ of length $7 \mathrm{cm}.$ Find a point $\mathrm{Z}$ on it such that $\mathrm{XZ}=2.5 \mathrm{cm}$Using a ruler and compasses, construct a perpendicular $\overline{\mathrm{XY}}$ through $\mathrm{Z}$.

Construct a circle of radius $4 \mathrm{cm}$. Name the centre as $\mathrm{O}$. Now draw a chord $\mathrm{AB}$ and construct a perpendicular from $\mathrm{O}$ on the chord $\mathrm{AB}$. Name the point where the perpendicular intersects the chord $\mathrm{AB}$ as $\mathrm{M}$. Measure the lengths of $\overline{\mathrm{AM}}$ and $\overline{\mathrm{MB}}$. What do you conclude?

Draw an angle measure $40˚$ by using a protractor. Now using compass and a ruler and construct an angle equal to the given angle.