1. **Problem Statement:** Determine if the two given planar graphs (a) G and (b) H are isomorphic, meaning they have the same structure in terms of vertices and edges. 2. **Definition of Isomorphism:** Two graphs are isomorphic if there is a one-to-one correspondence between their vertex sets that preserves adjacency (edges). 3. **Step 1: Compare number of vertices and edges.** - Graph G has 9 vertices. - Graph H has 10 vertices. 4. **Step 2: Check vertex count difference.** - Since the number of vertices differs (9 vs 10), the graphs cannot be isomorphic. 5. **Conclusion:** - Because isomorphic graphs must have the same number of vertices, graphs G and H are **not isomorphic**. This is a fundamental property: differing vertex counts immediately disqualify isomorphism without further checks.