Help me im dummmy head

Find the total area for the regular pyramid ( follow the answer set up in the picture)

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 have 138.72 in your saving account u take out 45.23 and 18.00 you deposit 75.85 into your account