Any portion of the circumference of a circle is called a(n)

a. diameter
b. radius
c. center
d. arc

Astick 2 m long is placed vertically at point b. the top of the stick is in line with the top of a tree as seen from point a, which is 3 m from the stick and 30 m from the tree. how tall is the tree?

Idon’t know what to do after i plot my first shape

The life (in hours) of a magnetic resonance imagining machine (mri) is modeled by a weibull distribution with parameters β = 2 and δ = 370 hours. (a) determine the mean life of the mri. (round your answer to 2 decimal ) determine the variance of the life of the mri. (round your answer to 1 decimal ) what is the probability that the mri fails before 250 hours? (round your answer to 4 decimal places.)