Chords, secants, and tangents how long is x?

if you could explain to me how to solve it, it’d be very much appreciated:)

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

Arectangle has a width of 9 units and length of 40 units. what is the length of a diognal. a. 31 unitsb. 39 unitsc. 41 units d. 49 units

Tom is the deli manager at a grocery store. he needs to schedule employee to staff the deli department for no more that 260 person-hours per week. tom has one part-time employee who works 20 person-hours per week. each full-time employee works 40 person-hours per week. write and inequality to determine n, the number of full-time employees tom may schedule, so that his employees work on more than 260 person-hours per week. graph the solution set to this inequality.