Finding the Fourth Proportional to 1,390.22, 1,917.40 and 892.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.22 : 1,917.40 = 892.91 : x
2. Step 2: Convert to fraction form
   1,390.22/1,917.40 = 892.91/x
3. Step 3: Cross multiply
   1,390.22x = 1,917.40 × 892.91
4. Step 4: Simplify right side
   1,390.22x = 1,712,061.17
5. Step 5: Solve for x
   x = 1,712,061.17/1,390.22
6. Step 6: Final answer
   x = 1,231.50