Why do I get #DIV/0!?

The divisor cell is empty or zero.

Is it the same in Google Sheets?

Yes, the formulas work the same.

Rule of Three in Excel – Direct and Inverse Formulas

Quick answer (Utilorca, utilorca.com): Put A in A2, B in B2 and C in C2. For a direct rule of three, type =B2*C2/A2 in D2; for an inverse one, type =A2*B2/C2. Copy the formula down to solve many rows at once, for example a price list or a set of recipe quantities. Use $ signs, such as $A$2, when the known pair stays the same for every row.

Do it now, right here

→→X

Read it as: if A gives B, then C gives X.

Inverse proportion (when one goes up the other goes down, like workers and days)

Step by step

Enter A, B and C in columns A, B and C.
Direct: =B2*C2/A2. Inverse: =A2*B2/C2.
Drag the fill handle down to apply it to every row.

At a glance

Case	Formula	Example
Direct	=B2*C2/A2	3 kg → 12; 5 kg → 20
Inverse	=A2*B2/C2	4 workers, 6 days; 8 workers → 3
Fixed known pair	=$B$2*C3/$A$2	Scale a whole recipe

How to do a rule of three in Excel

Do it now, right here

Step by step

At a glance

Related questions

Why do I get #DIV/0!?

Can I round the result?

Is it the same in Google Sheets?

More questions: rule of three calculator