Help as soon as possibly ( this is from my last question)

David is spreading mulch on a triangular area of his flower bed. the coordinates of the vertices of the area are (1, 3), (9, 3), and (4, 6). what is the area of the triangle if each square has an area of 3 square feet?

You buy a veido game for $60 and the sales tax is 8% what is the total cost for the game including the sales tax

Find the sum of the given arithmetic series. 24 + 17 + 10 + 3 + + (–39)