The Determination Chart in Form 1127 is used to help taxpayers determine which section of the form to complete based on their specific situation. The chart lists various reasons for requesting an extension of time to file a return and/or pay taxes, such as being outside the United States, needing more time to obtain records, or having a casualty or disaster. Each reason corresponds to a specific section of the form that taxpayers must complete to request an extension. The chart also provides instructions for completing each section and calculating any required penalties or interest.