This is a Civil Engineering Problem and is typical of the problems that you solve as a Civil Engineering student.
OF course, the problems do get much - much more complicated, but these basic principals will take you a long way to solving Civil Engineering Mechanics Problems.
I like it because is combines heavy trig. with lots of vector calculus with drafting for insight while using theory of mechanics and applies all the mathematics that a student previously has learned.
1) The problem wanted the Stress in the Axial Direction; Equation 3 under - stress
2) The problem wanted the equation for strain that represents the lengthening of the sloped round bar; "L" is the original Length of the round bar before stretching. The Boxed delta epsilon equation.
3) " W " is the load being applied to the sloped round cross - sectional - bar...