Shooting uphill or downhill is confusing for many because gravity does not act perpendicular to the direction the bullet is traveling. Thus, gravity must be divided into its component vectors. Only the fraction of gravity equal to the cosine of the angle of fire with respect to the horizon affects the rate of fall of the bullet, with the remainder adding or subtracting negligible velocity to the bullet along its trajectory. To find the correct zero, the sniper multiplies the actual distance to the range by this fraction and aims as if the target were that distance away. For example, a sniper who observes a target 500 meters away at a 45-degree angle downhill would multiply the range by the cosine of 45 degrees, which is 0.707. The resulting distance will be 353 meters. This number is equal to the horizontal distance to the target. All other values, such as windage, time-to-target, impact velocity, and energy will be calculated based on the actual range of 500 meters. Recently, a small device known as a cosine indicator has been developed. This device is clamped to the tubular body of the telescopic sight, and gives an indicative readout in numerical form as the rifle is aimed up or down at the target. This is translated into a figure used to compute the horizontal range to the target.