$d = \sqrt{6^2 + 6^2}$
$d = 6\sqrt{2}$
$A_1 = 6(6)$
$A_1 = 36 \, \text{ ft}^2$ → side and front
$A_2 = 6d = 6(6\sqrt{2})$
$A_2 = 36\sqrt{2} \, \text{ ft}^2$ → diagonal
Required lateral area
$A = 2A_1 + A_2$
$A = 2(36) + 36\sqrt{2}$
$A = 122.91 \, \text{ ft}^2$ answer