Can you me understand how to do this?

Which of the following is a function? a.) {(-2, -4/5), (-1,-,,-1)} b.) {(-2,,1/,3/,1)} c.) {(-22)} d.) {(-21)}

Find the interior angle of a regular polygon which has 6 sides

Acompany makes steel lids that have a diameter of 13 inches. what is the area of each lid? round your answer to the nearest hundredth