Does anyone know the answer if so please tell me ty!

The perimeter of a square is80-64y units. which expression can be used to show the side length of one side of the square?

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

Thales was an ancient philosopher familiar with similar triangles. one story about him says that he found the height of a pyramid by measuring its shadow and his own shadow at the same time. if the person is 5-ft tall, what is the height of the pyramid in the drawing?