Question

Construct the following angles at the initial point of a given ray and justify the construction 90°. 

Answer 1

Steps of construction:
1. Draw a line segment AB.
2. With center A and any radius draw in arc which intersect AB at C.
3. With center C and same radius draw an arc which intersects previous arc at D.
4. With centers D same radius draw an arc which intersects are in (2) at E.
5. With centers E and D same radius more than `1/2`ED draw an arc cutting each other at F.
6. Join FA
∴ `∠`FAB = 90°