Structural Geology: Analysis of Dip and Strike

Determine the angle of dip in the following
The dip angle is
Contour lines (thinner lines) between index contours are called
Which of the following is true for Direction of dip
Contour map is given below based on it answer the following questions with best possible answer.?

Scale: 1cm=100m
Given that: AD=1.80cm, AB=1.15m, BD=0.6cm, DC=0.5cm, CE=1m