How do I find 75% of 400

Plot the points (0,6), (3,15.8), and (9.5,0) using the graphing tool, and find the function

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil

Which of the following statements would be sufficient to prove that parallelograms pqrs is a rectangle ?