PLS HELP (AGAIN) ILL MARK BRAINLIEST. I HAVE TO TURN THIS IS ASAP

Step-by-step explanation:

A diameter spans from one end of (in this case, a circle) to the direct opposite end, going through the center-point. The radius, on the other hand, is half of a diameter, and spans only from the center-point to a point on the circle.

In this case:

1) Diameter = 18 km (given)

  Radius = 18/2 = 9 km

2) Diameter = 1 x 2 = 2 m

   Radius = 1 m (given)

3) Diameter = 17 x 2 = 34 cm

   Radius = 17 cm (given)

4) Diameter = 50 mm (given)

  Radius = 50/2 = 25 mm

John has a swimming pool, in which the center of the pool to the edge is 3 meters. What is the diameter? Simply multiply 3 with 2:

3 x 2 = 6 meters

6 meters is the diameter.