Step 1: Recall the polar form for a circle.
For the circle
\[
x^2+y^2=c^2
\]
the polar of a point \((x_1,y_1)\) is given by
\[
xx_1+yy_1=c^2
\]
Step 2: Compare the given line with the polar equation.
The given line is
\[
\frac{x}{a}+\frac{y}{b}=1
\]
Multiplying by \(c^2\), we can write it as
\[
x\cdot \frac{c^2}{a}+y\cdot \frac{c^2}{b}=c^2
\]
Step 3: Identify the pole.
Comparing
\[
xx_1+yy_1=c^2
\]
with
\[
x\cdot \frac{c^2}{a}+y\cdot \frac{c^2}{b}=c^2,
\]
we get
\[
x_1=\frac{c^2}{a},\qquad y_1=\frac{c^2}{b}
\]
Therefore, the pole of the given line is
\[
\left(\frac{c^2}{a},\frac{c^2}{b}\right)
\]
Step 4: Final conclusion.
Hence, the required pole is
\[
\boxed{\left(\frac{c^2}{a},\frac{c^2}{b}\right)}
\]