A circle has a radius of 13 inches.
Which equation can be used to find the diameter of this circle?
od=21(13)
ed= }(13)
od=2(13)
d=13²
Please help me!

Find a parametrization for the curve「and determine the work done on a particle moving along γ in r3 through the force field f: r^3--r^3'where f(x, y,z) = (1,-x, z) and (a) im (γ) is the line segment from (0,0,0) to (1,2,1) (b) im (γ) is the polygonal curve with successive vertices (1,0,0), (0,1,1), and (2,2,2) (c) im (γ) is the unit circle in the plane z = 1 with center (0,0,1) beginning and ending at (1,0,1), and starting towards (0,1,1)