a$)$ Two scan lines are given for the following polygon.

$[2]$

Write the depth value $(Z)$ equation for the next given co$-$ordinate positions $(Z_{x+1}^{\text{'}})$ and $(Z_{y+1}^{\text{'}\text{'}}).$

b$)$ Given two triangles P with vertices $P1(100,100,50),P2(50,50,50),P3(150,50,50)$ and $Q$ with vertices Q$140,80,60,$ Q$2(70,70,50),$ Q$3(10,75,70),$ determine which triangle should be painted first using the scanline method.

$3$

c$)$ What is the advantage of coherence property in graphical representation of a scene?

$2$