The main administrative divisions of the byzantine empire were called which were governed by various
a) cabinets / secretaries
b) themes / generals
c) kingdoms /kings
d) capitals / governors

b) themes / generals is the correct answer.

Explanation:

The Byzantine Empire was a huge and strong civilization.In the Byzantine-Arab fights, the Arabs have destroyed the Byzantine Empire, so to fight back they formed a new military system called theme system.

The main administrative divisions of the Byzantine empire were called themes.

Hence,the themes were the main administrative units of the middle Byzantine Empire. which were governed by various generals.

angle a = 40.6°

step-by-step explanation:

for any right angle triangle we know the pythagoras theorem reveals

hypotenuse² = height²+base²

by this formula we will calculate the length of hypotenuse

h² = 6²+7²

⇒ h =√36+49 = √85 = 9.22

now from the given triangle sin a = height/ hypotenuse

                                                sin a = 6/9.22 = 0.651

therefore

so angle a = 40.6°