Remember that the diameter is the entire distance from one edge to another one straight across (It has to pass through the center point of the circle!). Half of the diameter is the radius.
r = d/2
Where, r is the radius, and d is the diameter.
The Area of a Circle can be found using this formula:
A = πr^2
r = 1.7/2
A = π*(1.7/2)^2
A = π * (1.7*1.7)/(2*2)
A = π * 2.89 / 4
A = 0.7225π