3×ra

3×ra is a mathematical expression that means three times the quantity ra. The exact meaning depends on what ra denotes in a given context. In pure mathematics, if ra is a real-valued variable or parameter, 3×ra simply equals 3ra, a scalar multiple.

In programming and notation, the concept is the same but the symbol used for multiplication can vary. Many programming languages write this as 3 * ra, since the cross symbol × is not always available or convenient in code.

In astronomy, ra commonly stands for right ascension, an angular coordinate used to locate objects on the celestial sphere. Right ascension is typically expressed in hours, minutes, and seconds or converted to degrees or radians. If one writes 3×ra for right ascension, it is not a standard astronomical quantity by itself. Interpreting it physically would require converting to a linear angle and considering the periodic nature of RA. For example, if ra is 5 hours, 3×ra would be 15 hours; if ra is 9 hours, 3×ra = 27 hours, which wraps around modulo 24 hours to 3 hours. If ra is given in radians, multiplying by 3 yields 3×ra radians, which would be reduced modulo 2π to stay within a full circle.

Ambiguities can also arise when ra is used as a short name for other quantities (for example, a radius component or a variable in a specific model). In any formal use, it is important to define ra’s meaning, units, and any necessary modular reductions.