What area of mathematics is used to calculate parallax? algebra
geometry
calculus
trigonometry

algebra

Explanation:

The parallax formula states that the distance to a star is equal to 1 divided by the parallax angle,  

p

, where  

p

is measured in arc-seconds, and  

d

is parsecs.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.