Quick questions on Geometric constructions and loci explained: O-Level E-Maths

The perpendicular bisector of a segment $AB$ is constructed by opening the compasses to more than half of $AB$ and drawing arcs from both $A$ and $B$ above and below the line; the line through the two arc intersections is the perpendicular bisector. Every point on it is equidistant from $A$ and $B$.

To bisect an angle, draw an arc from the vertex crossing both arms, then from those two crossing points draw two more arcs that meet; the line from the vertex through that meeting point bisects the angle. Every point on it is equidistant from the two arms.

Describe the locus of points $5\ \text{cm}$ from a fixed point $P$. [1 mark]

What construction gives the locus of points equidistant from two intersecting lines? [1 mark]

A point must be within $3\ \text{cm}$ of $A$ and equidistant from $A$ and $B$. Describe the locus. [2 marks]