The formula to calculate the ground speed is:
\[ V_g = \cos(a) \times v_{tas} + ws \]
Where:
Ground speed is defined as the horizontal component of the velocity of an aircraft relative to the Earth's surface.
Example:
Step 1: Convert the angle to radians:
\[ a = 30^\circ = \frac{\pi}{6} \text{ radians} \]
Step 2: Calculate the ground speed:
\[ V_g = \cos\left(\frac{\pi}{6}\right) \times 150 + 20 \approx 129.9 + 20 = 149.9 \text{ knots} \]