Use the image to answer the question.
An illustration shows a 10 by 10 grid. A non-right triangle is enclosed within the grid. The first vertex is at the top of row 3 and the right of column 3. The second vertex is at the bottom of row 10 and the left of column 1. The third vertex is at the bottom of row 10 and the right of column 10.
What is the area of the non-right triangle? The base and height are found by counting the squares.
The base of the triangle is 9 squares (from column 3 to column 10 along row 10), and the height is 7 squares (from row 3 to row 10 along column 3).
Therefore, the area of the triangle is:
Area = 0.5 x base x height
Area = 0.5 x 9 x 7
Area = 31.5 square units.