#### Bisect a straight angle, using ruler and compasses. Measure each part.

Steps of construction:

• Draw a line AB of any length using ruler.
• Draw an arc of any radius taking center O  which cuts the line AB at points P and Q.
• Draw arcs at center P and Q with the same radius more than half of PQ which intersect each other at R.
• Draw a line that joins OR and produce it to any point C.

Now we can measure anngle $\angle \mathrm{BOC}=\angle A O C=90^{\circ}$