When doing rise/run which direction do the points go left or right ?

What is the area of the triangle 10 13 12

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?

Iwill give you ! what is the measure of ∠v ?