The next step in the process after defining tasks, durations, resources, and costs is to seek baseline approval. A baseline is an approved version of a project plan that serves as a reference point for measuring progress and performance throughout the project lifecycle. A baseline typically includes scope, schedule, cost, quality, and risk parameters. Seeking baseline approval involves presenting the project plan to key stakeholders and obtaining their formal agreement on the project objectives and deliverables. Baseline approval can help to establish clear expectations, avoid scope creep, and facilitate change control during project execution.

The NEXT step after defining tasks, durations, resources, and costs during the planning phase is to seek baseline approval. Baseline approval involves finalizing the project plan and gaining approval from stakeholders, establishing the plan as the baseline for the project's performance. References: CompTIA Project+ Study Guide Section 3.4.1