10, 15 Non-linear Pattern Rules - Triangular Numbers 1, 3, 6,

Each number represents the number of dots needed to form an equilateral triangle. To find the next number in the sequence, you simply add a new row of dots to the base of the previous triangle. 4. Apply the formula

Because the second difference is constant (always 1), the sequence is quadratic. This means the rule involves an n2n squared : Explicit Rule : 3. Visualize the geometry Triangular Numbers 1, 3, 6, 10, 15 Non-Linear Pattern Rules

T100=100(100+1)2=50×101=5050cap T sub 100 equals the fraction with numerator 100 open paren 100 plus 1 close paren and denominator 2 end-fraction equals 50 cross 101 equals 5050 ✅ Answer The rule for the triangular number sequence is Each number represents the number of dots needed

To find any term without listing the whole sequence, plug the position into the explicit formula. For example, to find the 100th triangular number: Apply the formula Because the second difference is