To find the value of [tex]\( x \)[/tex] in the proportion [tex]\(\frac{0.7}{4} = \frac{x}{12}\)[/tex], follow these steps:
1. Set up the equation: We start by writing the proportion as an equation:
[tex]\[
\frac{0.7}{4} = \frac{x}{12}
\][/tex]
2. Cross-multiply: To eliminate the fractions, we can use cross-multiplication. This means we multiply the numerator of one fraction by the denominator of the other, and set the products equal to each other:
[tex]\[
0.7 \cdot 12 = 4 \cdot x
\][/tex]
3. Simplify the equation: Multiply the numbers on both sides of the equation:
[tex]\[
0.7 \cdot 12 = 8.4
\][/tex]
So, the equation becomes:
[tex]\[
8.4 = 4 \cdot x
\][/tex]
4. Solve for [tex]\( x \)[/tex]: To isolate [tex]\( x \)[/tex], divide both sides of the equation by 4:
[tex]\[
x = \frac{8.4}{4}
\][/tex]
5. Perform the division: When you divide 8.4 by 4, you get:
[tex]\[
x = 2.1
\][/tex]
Therefore, the value of [tex]\( x \)[/tex] that satisfies the given proportion is [tex]\( 2.1 \)[/tex]. So, the correct choice is:
b. 2.1
