Chief Delphi - C Programming Homework Help Needed

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C Programming Homework Help Needed

Hi all,
I'm taking an course, "Structured Programming in C" and am having some issues with my homework for the week.
My assignment is to write a program that calculates various aspects of projectile motion, but I am running into a problem with an output(?) in my program.

When I compile the program I receive no errors or warnings, but when I try to enter values into the first input, it turns the value into '+NAN'. I don't know what '+NAN' is or how to fix it.
I've attached a screen capture of what happens when the program is run and values are entered.

HELP!

Please excuse the messiness of the code, as it is not completed or functional.

Code:

/*

 * Author:        Patrick McCarthy

 * Filename:        P34.c

 * Description:        Homework 2, Chapter 3:4, CS261

 *         This program computes the duration of a projectile's flight

 *         and its height above the ground when it reaches the target.

*/



#include <stdio.h>

#include <math.h>



/* Function prototype */

float find_radians(float theta);



/* Function prototype */

float calculate_time(float distance, float velocity, float theta);



/* Function prototype */

float calculate_height(float velocity, float theta, float time);





int main(void)

{

        float degree;

        float theta;

        float distance;

        float velocity;

        float time;

        float height;



        /* Gets the angle of elevation from the user */

        printf("Enter angle (in degrees) of elevation =>");

        scanf("%f",&degree);



printf("%f degrees\n", &degree);



        theta = find_radians(degree);

        

        printf("%f radians\n", &theta);



        /* Gets the distance to the target from the user */

        printf("Enter distance (in feet) to target =>");

        scanf("%f" ,&distance);



        /* Gets the projectile's velocity from the user */

        printf("Enter projectile's velocity (ft/sec) =>");

        scanf("%f", &velocity);



        calculate_time(distance,velocity,theta);



        /* Displays time of projectile flight to user */

        printf("Time of flight is %f seconds.\n", &time);

        

        calculate_height(velocity,theta,time);



        /* Displays height of projectile at impact to user */

        printf("Height of projectile impact is %f feet from the ground.\n", &height);



        return 0;

}





/* Converts degrees to radians */

float find_radians(float degree)

{

        float theta;        /* local variable */

        float Pi = 3.14159;

        

        theta = degree * (180/Pi);



        return (theta);

}





float calculate_time(float distance,float velocity,float theta)

{

        float time;        // local variable

        

        time = distance / ( velocity * cos(theta) );



        return (time);

}





float calculate_height(float velocity, float theta, float time)

{

        float height;                // local variable

        float g = 32.17;        // Declares acceleration due to gravity as -32 ft/s/s



        height = velocity * sin(theta) * time - ( (g * time*time) / 2 );



        return (height);

}

Thanks!