8.3

4: The ray MA cuts the segment exactly in half.

9: Set up an equation showing that the two halves are equal.

15: Use the midpoint formula to solve for the coordinates of the midpoint.

21: Use the midpoint formula to solve for the coordinates of the unknown endpoint.

26: Use the distance formula, or sketch a right triangle and use the Pythagorean theorem.

35: The midpoint is in the middle, and the endpoint is the same distance from the midpoint as the midpoint is from the other endpoint.

46: The area of a rectangle is base times height, and the perimeter is the sum of the side lengths.

49: A triangle is half of a rectangle.

52: Flip the sign when dividing by a negative number.