Finding the Fourth Proportional to 1,401.78, 1,934.10 and 812.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.78 : 1,934.10 = 812.10 : x
2. Step 2: Convert to fraction form
   1,401.78/1,934.10 = 812.10/x
3. Step 3: Cross multiply
   1,401.78x = 1,934.10 × 812.10
4. Step 4: Simplify right side
   1,401.78x = 1,570,682.61
5. Step 5: Solve for x
   x = 1,570,682.61/1,401.78
6. Step 6: Final answer
   x = 1,120.49