Idon't understand explain i would really appreciate it(srry for caps)

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?

How can you construct perpendicular lines and prove theorems about perpendicular lines

Vertical angles must check all that apply