Which explains why the sequence 81,3,1/ is arithmetic or geometric

Pls never taught i’m really confused and i rlly need

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?

Why is it so easy to buy on impulse and overspend with a credit card? what could you do to counteract this tendency?