Answer:
57.6
Step-by-step explanation:
"Significant figures" refer to figures that have an actual contribution to a number's value.
They refer to all digits except those with "leading zero," which means having a zero digit before a specific number. For example, in the number 0234, the significant figures are 234.
The rule for adding and subtracting significant figures is to round off the answer to the least number of decimal places. However, when it comes to multiplying and dividing significant figures, you have round off the answer to the least number of significant digits.
Let's solve.
21.4
+15
17.17
4.003
57.573
Let's now round off to the least number of decimal places, which is the tenths. Since 0.5 is followed by a number greater than 5, we have to round it off to 6. Therefore, the answer is: 57.6