Finding the Fourth Proportional to 2,139.78, 3,212.61 and 1,100.64

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.78 : 3,212.61 = 1,100.64 : x
2. Step 2: Convert to fraction form
   2,139.78/3,212.61 = 1,100.64/x
3. Step 3: Cross multiply
   2,139.78x = 3,212.61 × 1,100.64
4. Step 4: Simplify right side
   2,139.78x = 3,535,927.07
5. Step 5: Solve for x
   x = 3,535,927.07/2,139.78
6. Step 6: Final answer
   x = 1,652.47