Finding the Fourth Proportional to 1,370.78, 2,053.57 and 814.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,370.78 : 2,053.57 = 814.31 : x
2. Step 2: Convert to fraction form
   1,370.78/2,053.57 = 814.31/x
3. Step 3: Cross multiply
   1,370.78x = 2,053.57 × 814.31
4. Step 4: Simplify right side
   1,370.78x = 1,672,242.59
5. Step 5: Solve for x
   x = 1,672,242.59/1,370.78
6. Step 6: Final answer
   x = 1,219.92