Please help me i do not understand o tried to work it out but it meets none of the answers?

What is the difference between regular convex and concave polygons

If sec theta = 5/3 and the terminal point determined by theta is in quadrant 4, then

Oscar and julie ashton are celebrating their 15th anniversary by having a reception hall. they have budgeted $4,500 for their reception. if the reception hall charges a $90 cleanup fee plus & 36 per person, find the greatest number of people that they may invite and still stay within their budget.