<u>Answer:</u>
<u>For a:</u> The answer is 
<u>For b:</u> The answer is 
<u>For c:</u> The answer is 127.6
<u>For d:</u> The answer is 
<u>Step-by-step explanation:</u>
Significant figures are defined as the figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
<u>Rules for significant figures:</u>
- Digits from 1 to 9 are always significant and have infinite number of significant figures.
- All non-zero numbers are always significant. For example: 654, 6.54 and 65.4 all have three significant figures.
- All zero’s between integers are always significant. For example: 5005, 5.005 and 50.05 all have four significant figures.
- All zero’s preceding the first integers are never significant. For example: 0.0078 has two significant figures.
- All zero’s after the decimal point are always significant. For example: 4.500, 45.00 and 450.0 all have four significant figures.
- All zeroes used solely for spacing the decimal point are not significant. For example : 8000 has one significant figure.
<u>Rule applied for the addition and subtraction is:</u>
The least precise number present after the decimal point determines the number of significant figures in the answer.
<u>Rule applied for the multiplication and division is:</u>
The number of significant digits is taken from the value which has least precise significant digits.
For the given options:
- <u>Option a:</u> (2.7)(8.632)
The given problem is a multiplication one.

Here, the least precise significant digits are 2. So, the answer is 
- <u>Option b:</u> (3.600 x 10^-4) / 45
The given problem is a division one.

Here, the least precise significant digits are 2. So, the answer is 
- <u>Option c:</u> 2.365 + 125.2
The given problem is an addition one.

Here, the least precise significant digits after decimal is 1. So, the answer is 127.6
- <u>Option d:</u> (4.753 x 10^4) - (9 x 10^2)
The given problem is a subtraction one.

Here, the least precise significant digits after decimal are 2. So, the answer is 