Convex lens has a diameter of 30mm and a depth of 5mm at the center. How far from the vertex is the focus.

Which of the following is a proper fraction? a. 9⁄8 b. 5⁄6 c. 7⁄3 d. 4⁄2

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?

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