Draw $\overline{\mathrm{AB}}$ of length $10 \mathrm{cm}$. Construct the perpendicular bisector of $\overline{\mathrm{AB}}$ and name it $\overline{\mathrm{PQ}}$. Take a point $\mathrm{D}$ on $\overline{\mathrm{PQ}}$ and measure the lengths of $\overline{\mathrm{DA}}$ and $\overline{\mathrm{DB}}$.

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 $\mathrm{Z}$.

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