What Angle Makes a Projectile Travel Equally in X and Y Directions?

[Xiju]

Homework Statement

I need to find the angle (theta) that when an object is launched from it, it will go the same distance vertically as horizontally. So if it went 100 feet up in the Y axis it also went 100 feet in the X axis. Thanks.
ps. can you show me how you got this answer?

Homework Equations

ViSin(theta)(time) - 1/2at^2 = delta Y

ViCos(theta) (2time) = delta X

The Attempt at a Solution

ViSin(theta)(time) - 1/2at^2 = ViCos(theta) (2time)

 

[Astronuc]

The equations are here

http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html#tra7

and

http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html#tra5


Basically one is solving for the Range = Max. altitude

So R = h, v_yo = v_o$sin\theta$