A touring cycle has wheels of diameter 70cm'

1
A touring cycle has wheels of diameter 70cm.
How many rotations does each wheel make for
every 10km travelled?
2
A door is in the shape of a rectangle with a
semi-circular arch. The rectangular part is 2m
high and the door is 90cm wide. What is the area
of the door?
3
What is the minimum information you need to be
able to find the circumference and area of a
circle? the length of an arc? the area of a
sector?
4
How would you go about finding the area of a
circle if you know the circumference?