Final answer:
A bar graph diagram that displays activity and timing of each activity is known as a Gantt Chart, which is valuable for visual project management.
Step-by-step explanation:
A bar graph showing the activity and the timing of each activity is known as a Gantt Chart. Gantt Charts are particularly useful in project management, as they allow you to visualize the start and finish dates of different elements of a project and track progress against planned activities.
While pie graphs, or pie charts as they are sometimes called, represent how a total is divided into parts, and line or bar graphs can be used to compare categories or show changes over time, it is the Gantt Chart that specializes in displaying activity duration over a period.