Round 645 to the nearest ten

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?

What is always true when two whole numbers are subtracted?

If a suspect is in possession of 20 grams of cocaine how many ounces does he possess what will the charge be