Finding the Fourth Proportional to 1,388.69, 1,910.61 and 1,201.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.69 : 1,910.61 = 1,201.58 : x
2. Step 2: Convert to fraction form
   1,388.69/1,910.61 = 1,201.58/x
3. Step 3: Cross multiply
   1,388.69x = 1,910.61 × 1,201.58
4. Step 4: Simplify right side
   1,388.69x = 2,295,750.76
5. Step 5: Solve for x
   x = 2,295,750.76/1,388.69
6. Step 6: Final answer
   x = 1,653.18