Convert 3.5 to a fraction.

To convert the decimal 3.5 to a fraction, start by recognizing that 3.5 can be expressed as a mixed number. The number 3.5 consists of the whole number 3 and the decimal part 0.5.

To convert 0.5 into a fraction, it is equivalent to 1/2. Therefore, we can write 3.5 as:

[ 3 + 0.5 = 3 + \frac{1}{2} ]

This can be rewritten as:

[ 3 \frac{1}{2} ]

Next, to express this mixed number as an improper fraction, we multiply the whole number (3) by the denominator of the fractional part (2) and add the numerator (1):

[ 3 \times 2 + 1 = 6 + 1 = 7 ]

This result is placed over the original denominator (2):

[ \frac{7}{2} ]

Thus, 3.5 as a fraction is ( \frac{7}{2} ), which corresponds to the correct choice. The other options do not represent the value of 3.5 correctly when expressed as a fraction.