  Which properties of an orbifold can we ``hear,'' i.e., which topological and
geometric properties of an orbifold are determined by its Laplace spectrum? We
consider this question for a class of four-dimensional K\"{a}hler orbifolds:
weighted projective planes $M:=\C P^2(N_1,N_2,N_3)$ with three isolated
singularities. We show that the spectra of the Laplacian acting on 0- and
1-forms on $M$ determine the weights $N_1$, $N_2$, and $N_3$. The proof
involves analysis of the heat invariants using several techniques, including
localization in equivariant cohomology. We show that we can replace knowledge
of the spectrum on 1-forms by knowledge of the Euler characteristic and obtain
the same result. Finally, after determining the values of $N_1$, $N_2$, and
$N_3$, we can hear whether $M$ is endowed with an extremal K\"{a}hler metric.
