Finding the Fourth Proportional to 8,971.78, 13,459.83 and 3,128.98

Step by Step Solution

1. Step 1: Write the proportion equation
   8,971.78 : 13,459.83 = 3,128.98 : x
2. Step 2: Convert to fraction form
   8,971.78/13,459.83 = 3,128.98/x
3. Step 3: Cross multiply
   8,971.78x = 13,459.83 × 3,128.98
4. Step 4: Simplify right side
   8,971.78x = 42,115,538.87
5. Step 5: Solve for x
   x = 42,115,538.87/8,971.78
6. Step 6: Final answer
   x = 4,694.22