Finding the Fourth Proportional to 1,009.91, 1,393.15 and 636.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,009.91 : 1,393.15 = 636.18 : x
2. Step 2: Convert to fraction form
   1,009.91/1,393.15 = 636.18/x
3. Step 3: Cross multiply
   1,009.91x = 1,393.15 × 636.18
4. Step 4: Simplify right side
   1,009.91x = 886,294.17
5. Step 5: Solve for x
   x = 886,294.17/1,009.91
6. Step 6: Final answer
   x = 877.60