\(4x^2 + 16y^2 = 16\)
⇒ \(\frac{x^2}4 + \frac{y^2}1 = 1\)
which is equation of an ellipse whose centre is (0, 0) and major axis is x-axis.

Enclosed area in first quadrant \(= \frac {\pi ab}4\)
\(= \frac{\pi \times 2\times 1}4\)
\(= \frac \pi 2\) sq. units