Calculate Horizontal Range of Projectile - Unit Vector Velocity

[George3]

Homework Statement

Exactly 2.9 seconds after a projectile is fired it has the velocity (9.0i +4.5j) m/s.
What is the horizontal range of the projectile.

Homework Equations

The Attempt at a Solution

Range = [((9.0i^2 + 4.5j^2)^1/2)^2 x sin2(arctan(4.5/9))]/ 9.8 m/s/s
Range = 8.3 m but this is incorrect.

 

[D H]

Of course that's not correct. Look at the units, for one thing. For another, you aren't accounting for that 2.9 seconds.