The Bessemer process<span> was the first inexpensive industrial </span>process<span> for the mass-production of steel from molten pig iron before the development of the open hearth furnace. The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron.</span>
A fundamental principle of the Articles of Confederation is A. Permanent unity between the states. (Apex)
The sum of interior angles of a regular polygon is 360—
So add up the angles given and subtract that number from 360—
Answer: 136
