Answer
Sine of the angle = 0.9142857
Angle = $66.1^{0}$
Work Step by Step
Given area 'A' = 16 sq inch
Lengths of sides-
a = 5 inch and b = 7 inch
Let the angle included by these sides is $\theta$
We know that-
A = $ \frac{1}{2}$ a b $\sin \theta$
i.e. $\sin \theta$ = $\frac{2 A}{a b}$
= $\frac{2 \times 16}{5\times7}$
=$\frac{32}{35}$ = 0.9142857
i.e $\sin\theta$ = 0.9142857 = Required Answer
$\theta$ = $\sin^{-1}0.9142857$ = $66.1^{0}$
