Finding the Fourth Proportional to 1,387.72, 1,914.91 and 798.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.72 : 1,914.91 = 798.45 : x
2. Step 2: Convert to fraction form
   1,387.72/1,914.91 = 798.45/x
3. Step 3: Cross multiply
   1,387.72x = 1,914.91 × 798.45
4. Step 4: Simplify right side
   1,387.72x = 1,528,959.89
5. Step 5: Solve for x
   x = 1,528,959.89/1,387.72
6. Step 6: Final answer
   x = 1,101.78