Arc Length and Radians question- please help! Will mark brainliest! Is 20pts!

The answer is shown but please give me an explanation so I can show my work!

In the diagram, the measure of angle 9 is 85° which angle must also measure 85°?

What happens to the area as the sliders are adjusted? what do you think the formula for the area of a triangle is divided by 2?

Which best describes a central bank's primary goals? limiting inflation and reducing unemployment reducing unemployment and maintaining cash flow controlling stagflation and reducing unemployment managing credit and ensuring the money supply's liquidity