Finding the Fourth Proportional to 91,900.40, 128,923 and 91,900.40

Step by Step Solution

1. Step 1: Write the proportion equation
   91,900.40 : 128,923 = 91,900.40 : x
2. Step 2: Convert to fraction form
   91,900.40/128,923 = 91,900.40/x
3. Step 3: Cross multiply
   91,900.40x = 128,923 × 91,900.40
4. Step 4: Simplify right side
   91,900.40x = 11,848,075,269.20
5. Step 5: Solve for x
   x = 11,848,075,269.20/91,900.40
6. Step 6: Final answer
   x = 128,923