Cable $DB$ supports canopy beam OABC as shown in the figure.

a$)$ Find the required cross$-$sectional area of cable $BD$ if the allowable normal stress is $200$MPa. $(20\%)$

b$)$ Determine the required diameter of the pins at $O$ if the allowable stress in shear is $120$MPa. $($Hint: use resultant force at $O$ and The pin at $O$ is in double shear.

c$)$ Determine the elongation and strain of the cable DB if $E=180$Gpa. $($Consider the area of the cable DB as it is calculated in part $($a$))(20\%)$

Assume that canopy beam weight is $W=11kN.$