Finding the Fourth Proportional to 1,393.31, 2,087.94 and 653.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,393.31 : 2,087.94 = 653.15 : x
2. Step 2: Convert to fraction form
   1,393.31/2,087.94 = 653.15/x
3. Step 3: Cross multiply
   1,393.31x = 2,087.94 × 653.15
4. Step 4: Simplify right side
   1,393.31x = 1,363,738.01
5. Step 5: Solve for x
   x = 1,363,738.01/1,393.31
6. Step 6: Final answer
   x = 978.78