Question

Solve for r in the proportion.

20
45
=
12
r


r =

Answer 1

To solve for \( r \) in the proportion

\[
\frac{20}{45} = \frac{12}{r},
\]

we can use cross-multiplication. This means we multiply the numerator of one fraction by the denominator of the other fraction:

\[
20 \times r = 12 \times 45.
\]

Calculating \( 12 \times 45 \):

\[
12 \times 45 = 540.
\]

Thus, we have:

\[
20r = 540.
\]

Now, to solve for \( r \), divide both sides by 20:

\[
r = \frac{540}{20}.
\]

Calculating \( \frac{540}{20} \):

\[
r = 27.
\]

Therefore, the value of \( r \) is

\[
\boxed{27}.
\]