Finding the Fourth Proportional to 1,405.55, 2,105.90 and 972.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.55 : 2,105.90 = 972.20 : x
2. Step 2: Convert to fraction form
   1,405.55/2,105.90 = 972.20/x
3. Step 3: Cross multiply
   1,405.55x = 2,105.90 × 972.20
4. Step 4: Simplify right side
   1,405.55x = 2,047,351.12
5. Step 5: Solve for x
   x = 2,047,351.12/1,405.55
6. Step 6: Final answer
   x = 1,456.62