A light, single$-$engine aircraft has a wing area of $15\mathrm{.}8m^2$ and wing span of $9\mathrm{.}75$ m $.$ It's maximum gross weight is $1110$ kg $.$ The wing use an NACA $65-425$ airfoil, which has a lift slope of $\frac{0\mathrm{.}1033}{?}$ degree, and zero lift angle of attack of $-3.$ Assume $=0\mathrm{.}12.$ If the airplane cruising at $54\frac{m}{s}$ at standard see level at its maximum gross weight, calculate the geometric angle of attack of the wing.