Answer: 70.5 km/h
Justification:
The question is not clearly stated but it seems you are asking for the x - component of the velocity of the helicopter.
You can find the x and y - components of the velocity using the trigonometric ratios sine and cosine.
The sine ratio relates the y-component and the velocity by:
sin(angle) = y-component of velocity / velocity
The cosine ratio related the x-component and the velocity by:
cos(angle) = x-component of velocity / velocity.
Since you have the angle and the velocity and are asked by the x-component of the velocity, you need to use the cosine ratio:
cos(35°)= x-component / 86.0 km/h
=> x -component = 86.0 km/h * cos(35°) = 70.5 km/h
