The stress concentration factor, K for a flat bar with a centric hole under axial loading is: 3 (27) + 3.66 (27) - 1.53 (²7) where: K= 3.00-3.13 r-radius of the hole, and D-the width of the bar, If D=75 mm, approximate the value of r to obtain K-3.5. (a) Determine your result using Bisection and Secant method. All data /values shall be in 4-decimal place. Do iteration up to five (5) iteration or stop if two consecutive r values are less than 0.001. (Hint: r is somewhere between 4 and 6 mm. Use this value as initial guess) (b) Discuss the differences of the answers from Q5(a).