Finding the Fourth Proportional to 1,381.13, 1,906.36 and 821.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.13 : 1,906.36 = 821.99 : x
2. Step 2: Convert to fraction form
   1,381.13/1,906.36 = 821.99/x
3. Step 3: Cross multiply
   1,381.13x = 1,906.36 × 821.99
4. Step 4: Simplify right side
   1,381.13x = 1,567,008.86
5. Step 5: Solve for x
   x = 1,567,008.86/1,381.13
6. Step 6: Final answer
   x = 1,134.58