Answer
$51.6^{\circ}$.
Work Step by Step
The maxima are located by $d sin \theta = m \lambda$. The order is the value of m.
$$d sin \theta_1 = \lambda$$
$$d sin \theta_4 = 4 \lambda$$
$$sin \theta_4 = 4 sin \theta_1=4 sin 11.3^{\circ}$$
$$\theta_4 = sin^{-1} (4 sin 11.3^{\circ})=51.6^{\circ}$$
