Projectile Motion: Solving for Range at Various Launch Angles

[ama]

Homework Statement

A shot-putter throws the shot with an initial speed of 4.0 m/s from a height of 4.5 ft above the ground. Calculate the range of the shot for each of the following launch angles.
a. 20 degrees
b. 30 degrees
c. 40 degrees
Vo=4
yo=4.5

Homework Equations

y = yo + Vo*sinθ*t - 1/2*g*t^2.
x = Vo*cosθ*t.

The Attempt at a Solution

I tried solving for the time in the first equation. I was careful to put in the height 4.5 for yo since it specifies that in the problem. I then tried to plug the time value into the second value. Then I repeated it for the other angles. Here is an example of what i did.
y=(4.5)+4(sin20)(t)-(1/2)(9.81)(t^(2))
y=4.5+1.36808t-4.9t^(2)
t=1.1081
x=4(cos20)(1.1081)
x=4.16509
For 30
4.1011499
For 40
3.8483
Yet for some reason these answers are wrong. Why?

 

[Doc Al]

I was careful to put in the height 4.5 for yo since it specifies that in the problem.

Note that the initial height was given in feet.

 

[tiny-tim]

welcome to pf!

hi ama! welcome to pf!

(try using the X² icon just above the Reply box )

… from a height of 4.5 ft
…
y=(4.5)+4(sin20)(t)-(1/2)(9.81)(t^(2))

erm …

feet! ​

 

[ama]

lol. I am so really new to physics.