
    In a personalized geometry learning module, students need to calculate specific points in a pattern where objects are arranged in decagonal shapes of increasing size. Given a student's progression level, determine the total number of objects needed to form a complete decagonal shape at that level, helping them understand geometric growth patterns.
    

    
def is_num_decagonal(n):
    """
    In a personalized geometry learning module, students need to calculate specific points in a pattern where objects are arranged in decagonal shapes of increasing size. Given a student's progression level, determine the total number of objects needed to form a complete decagonal shape at that level, helping them understand geometric growth patterns.
    

    """
def is_num_decagonal(n):
    """
    In a personalized geometry learning module, students need to calculate specific points in a pattern where objects are arranged in decagonal shapes of increasing size. Given a student's progression level, determine the total number of objects needed to form a complete decagonal shape at that level, helping them understand geometric growth patterns.
    

    """
    return 4 * n * n - 3 * n