Solve the Problem $$y = ( \tan \theta ) x - \frac { 16 } { v ^ { 2 } \cos ^ { 2 } \theta } x ^ { 2 }$$

Multiple Choice

Solve the problem.
-The altitude of a projectile in feet (neglecting air resistance) is given by
$$y = ( \tan \theta ) x - \frac { 16 } { v ^ { 2 } \cos ^ { 2 } \theta } x ^ { 2 }$$
where $x$ is the horizontal distance covered in feet and $v$ is the initial velocity of the projectile at an angle $\theta$ from $t$ ] horizontal. Find the firing angle (in degrees) of a projectile fired at an initial velocity of 100 feet per second so that it strikes the ground $312.5$ feet from the firing point.

A) $30 ^ { \circ }$
B) $45 ^ { \circ }$
C) $50 ^ { \circ }$
D) $22.5 ^ { \circ }$