Aflare is shot from a snowmobile with an initial velocity of 4.3 m/s at 90*, while the snowmobile is moving at 8.5 m/s at 0.0*. determine using both methods, graphical and mathematical, the initial net velocity (magnitude and direction) of the flare. how do i do this? ?

The driver is tooling along in his snowmobile, pointed north,
at 8.5 m/s.

He's carrying the flares with him, so the flares are also moving north
at 8.5 m/s.

When he fires the flare straight up, it has a vertical velocity of 4.3 m/s
straight up, and a horizontal velocity of 8.5 m/s towards the north.

The magnitude of the net velocity is √(4.3² + 8.5²) .
That's about  9.53 m/s, at some angle between straight up
and straight north.

The angle above horizontal is the angle that has a tangent of  4.3/8.5 .
I'll let you work out the angle.