Find the value of x in the triangle shown below.
5.7
20
6
6
56

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?

Find the missing dimension extra points

Prove that 16^4-2^13-4^5 is divisible by 11.