Given A(2,3) B(8,7) and C (6,1) which coordinate will make AB perpendicular to CD?

A. D(3,3)
B. D(4,4)
C. D(8,4)
D. D(9,3)

Detailed answer would be great!!

Problem fathi wants to print out a pdf document that is 48 pages long. to save paper, he decides to print on both sides of each sheet and to print two pages on each side of the sheet. how many sheets of paper will he need?

How many ordered pairs of positive integers satisfy xy=32?

A3cm×3cm\greend{3\,\text{cm} \times 3\,\text{cm}} 3cm×3cm start color greend, 3, space, c, m, times, 3, space, c, m, end color greend rectangle sits inside a circle with radius of 4cm\blued{4\,\text{cm}} 4cm start color blued, 4, space, c, m, end color blued . what is the area of the shaded region? round your final answer to the nearest hundredth.