Tensor Product, proof of isomorphism

Question

Let V and W be two vector spaces and

$$\Phi: Hom_K(\land^rV,W)\rightarrow Alt_K^r(V,W)\\ f \mapsto [(v_1,....,v_r)\mapsto f(v_1\land \cdot \cdot \cdot \land v_r)]$$

I need to show that $\Phi$ is an isomorphism.

I know we can define two bilinear maps but how would we show that they this map is isomorphic?