**Q6a) If the angle
between Citychain, Crabtree and the concierge is 90**^{◦}**, the distance between
Citychain and Crabtree is equal to the distance of
the concierge to Crabtree which also equals 45m, find the angle of Citychain, the concierge and Crabtree.**

**b) If P is the
midpoint between the concierge and Citychain, find
the distance between P and Crabtree**.