How many points are marked in Fig. 2.43?

What conclusion can be drawn from each part of Fig. 2.41, if

(a) DB is the bisector of ∠ADC?

(b) BD bisects ∠ABC?

(c) DC is the bisector of ∠ADB, CA ⊥ DA and CB ⊥ DB?

An angle is said to be trisected, if it is divided into three equal parts. If in Fig. 2.42, ∠BAC = ∠CAD = ∠DAE, how many trisectors are there for ∠BAE?

How many line segments are there in Fig. 2.43?

In Fig. 2.44, how many points are marked? Name them.