How many significant figures are in the number 78 x 10^12?

The number 78 x 10¹² can initially seem a bit confusing when it comes to determining the significant figures. Let’s break it down step by step.

First, we need to notice that in the number 78, both of the digits (7 and 8) are considered significant because:

• All non-zero digits are always significant.
• There are no leading zeros in this number that would affect the significant figure count.

Therefore, the digits ‘7’ and ‘8’ contribute a total of 2 significant figures.

Now, when we write the number in scientific notation as 78 x 10¹², the exponent (12) does not affect the number of significant figures. The exponent indicates the scale of the number but does not influence the count of significant figures derived from the coefficient, which is 78 in this case.

Thus, the conclusion is straightforward: the number 78 x 10¹² has 2 significant figures.