What is the value of the binary number 1001 in the decimal system?

To convert the binary number 1001 into the decimal system, each digit of the binary number is assigned a power of 2, starting from the rightmost digit, which represents (2^0) and moving leftwards. For the binary number 1001, the breakdown is as follows:

• The rightmost digit is 1, which is in the (2^0) position: (1 \times 2^0 = 1)

• The next digit to the left is 0, in the (2^1) position: (0 \times 2^1 = 0)

• The next digit is 0, in the (2^2) position: (0 \times 2^2 = 0)

• The leftmost digit is 1, in the (2^3) position: (1 \times 2^3 = 8)

Now, add these values together:

[

1 + 0 + 0 + 8 = 9

]

Therefore, the decimal equivalent of the binary number 1001 is 9. This confirms that the correct answer is indeed C, as the conversion reflects the accurate mathematical