Finding the Fourth Proportional to 3,420.54, 5,129.67 and 1,111.50

Step by Step Solution

1. Step 1: Write the proportion equation
   3,420.54 : 5,129.67 = 1,111.50 : x
2. Step 2: Convert to fraction form
   3,420.54/5,129.67 = 1,111.50/x
3. Step 3: Cross multiply
   3,420.54x = 5,129.67 × 1,111.50
4. Step 4: Simplify right side
   3,420.54x = 5,701,628.21
5. Step 5: Solve for x
   x = 5,701,628.21/3,420.54
6. Step 6: Final answer
   x = 1,666.88