Finding the Fourth Proportional to 91,128.60, 136,692.90 and 91,128.60

Step by Step Solution

1. Step 1: Write the proportion equation
   91,128.60 : 136,692.90 = 91,128.60 : x
2. Step 2: Convert to fraction form
   91,128.60/136,692.90 = 91,128.60/x
3. Step 3: Cross multiply
   91,128.60x = 136,692.90 × 91,128.60
4. Step 4: Simplify right side
   91,128.60x = 12,456,632,606.94
5. Step 5: Solve for x
   x = 12,456,632,606.94/91,128.60
6. Step 6: Final answer
   x = 136,692.90