Why are tenths, fifths, and fourths easy to convert to percent's?

Average acceleration: i have no idea how to do this.

Place the following steps in order to complete the square and solve the quadratic equation,

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?