Identify the starting value
Identify the ending value
Divide the ending value by the starting value
If needed, calculate the common ratio between terms
Use the formula: GP nth term = a × r^(n-1)
Use the formula: Sum of first n terms = a(r^n – 1) / (r – 1) for r ≠ 1
Use the formula: Sum to infinity = a / (1 – r) for |r| < 1
Substitute the known values into the relevant formula
Solve for the unknown value
Check the result against the sequence pattern