Finding the Fourth Proportional to 1,388.12, 1,914.72 and 1,055.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.12 : 1,914.72 = 1,055.81 : x
2. Step 2: Convert to fraction form
   1,388.12/1,914.72 = 1,055.81/x
3. Step 3: Cross multiply
   1,388.12x = 1,914.72 × 1,055.81
4. Step 4: Simplify right side
   1,388.12x = 2,021,580.03
5. Step 5: Solve for x
   x = 2,021,580.03/1,388.12
6. Step 6: Final answer
   x = 1,456.35