Add angle to Vector3

Hi, my first question, maybe a very noob question but I need some help …

let say that I want to shoot 3 bullets in different directions.

Please refer the img for reference.

26434-angles.jpg

Actually I´m using 3 diferent objects as targets, but I would like to have only one target and use angles to set the direction of the other 2.

this is what I’m using to get the direction:

fireDirection = (targetPosition - originPosition).normalized;

How can I add n degrees to my fireDirection?

Thanks in advance for your help, also apologize for my bad english u.u

I ended up with some trigonometry, thanks alot for all your help, you guys guided me to the solution.

here’s the code, I’ve tested it with Debug.DrawLine

Vector3[] CalculatePositionsForTripleDirection(){
		Vector3[] positions = new Vector3[3];

		float r = Vector3.Distance(bulletOriginPosition,targetPosition);
		float x = Mathf.Abs(bulletOriginPosition.x - targetPosition.x);
		float y = Mathf.Abs(bulletOriginPosition.y - targetPosition.y);
		float initialAngle = Mathf.Atan2(y,x) * Mathf.Rad2Deg;
		float secondAngle = (initialAngle + angleVariance) * Mathf.Deg2Rad;
		float thirdAngle = (initialAngle - angleVariance) * Mathf.Deg2Rad;

		//Calculate x2 and y2
		float x2 = r  * Mathf.Cos(secondAngle);
		float y2 = r  * Mathf.Sin(secondAngle);

		//Calculate x3 and y3
		float x3 = r  * Mathf.Cos(thirdAngle);
		float y3 = r  * Mathf.Sin(thirdAngle);

		//Verify if X is positive or negative
		if(targetPosition.x <  bulletOriginPosition.x){
			x2 = x2 *-1;
			x3 = x3 *-1;
		}

		//Verify if Y is positive or negative
		if(targetPosition.y < bulletOriginPosition.y){
			y2 = y2 * -1;
			y3 = y3 * -1; 
		}

		//Assign Values to positions
		positions[0] = targetPosition;
		positions[1] = new Vector3(bulletOriginPosition.x + x2, bulletOriginPosition.y + y2,targetPosition.z);
		positions[2] = new Vector3(bulletOriginPosition.x + x3,bulletOriginPosition.y + y3,targetPosition.z);
		return positions;
	}