Please help me with this question. "line segment AB is drawb on the grid with endpoints A(0,8) and B(6,0). Using only a straightedge and the grid itself divide AB into 4 congruent segments. Explain how you did this and why it works" please explain too

9.4.34  question   to estimate the height of a stone  figure, an observer holds a small square up to her eyes and walks backward from the figure. she stops when the bottom of the figure aligns with the bottom edge of the  square, and when the top of the figure aligns with the top edge of the square. her eye level is 1.811.81 m from the ground. she is 3.703.70 m from the figure. what is the height of the figure to the nearest hundredth of a  meter?