Finding the Fourth Proportional to 1,390.01, 1,917.42 and 1,224.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.01 : 1,917.42 = 1,224.62 : x
2. Step 2: Convert to fraction form
   1,390.01/1,917.42 = 1,224.62/x
3. Step 3: Cross multiply
   1,390.01x = 1,917.42 × 1,224.62
4. Step 4: Simplify right side
   1,390.01x = 2,348,110.78
5. Step 5: Solve for x
   x = 2,348,110.78/1,390.01
6. Step 6: Final answer
   x = 1,689.28