What basic trigonometric identity would you use to verify that (sin² x + cos² x/cos x) = sec x?

a. sin x = (1/csc x)
b. 1 + cot² x = csc² x
c. cos² x + sin² x = 1
d. tan x = (sin x/cos x)

Find the radius of a circle that has a circumference of 16. the formula for the circumference of a circle is c = 2tr, where r is the radius and c is the circumference. the equation solved for r is r = c over 2π. r=4 r= 8 r=12 r= 16