Answer
$(2.47,-1.02)$
Work Step by Step
Solve for $r$ using the formula $r=\sqrt {x^{2}+y^{2}}$ to obtain:
$$r=\sqrt {(1.3)^{2}+(-2.1)^{2}}=2.47$$
Since $(1.3, -2.1)$ is in the fourth quadrant, then
$$\theta= \tan^{-1}\left(\frac{y}{x}\right)=\tan^{-1}\left(\frac{-2.1}{1.3}\right)\approx-1.02$$
Thus, the polar coordinates for the point $(1.3, -2.1)$ can be given as $(2.47,-1.02)$.
