Science Buddies: "Ask an Expert"

Science Project Link:

https://www.sciencebuddies.org/science- ... #materials

In the Procedure section of this link, at the bottom, it shows 3 equations. In Equation 1.i it says, "If you are not sure how Equation 2 was derived from Equation 1, take a moment to examine the equations so that you understand the derivation process." I have been trying to figure out how it was derived for many days! Can somebody please help me figure it out? I hate how unspecific that sentence is and how it assumes everyone knows how it was derived!

Hello,

Equation 1 was rearranged by manipulating both sides. Whatever you do to one side of the equation must be done to both sides. I'll try to show here:

Equation 1
A / B = C / D

Multiply both sides by D:
(D * A) / B = C

Multiply both sides by B:
D * A = C * B

Divide both sides by A to yield Equation 2:
D = (C * B) / A

Hope this helps!

Audrey