Finding the Fourth Proportional to 1,388.07, 2,082.15 and 414.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.07 : 2,082.15 = 414.18 : x
2. Step 2: Convert to fraction form
   1,388.07/2,082.15 = 414.18/x
3. Step 3: Cross multiply
   1,388.07x = 2,082.15 × 414.18
4. Step 4: Simplify right side
   1,388.07x = 862,384.89
5. Step 5: Solve for x
   x = 862,384.89/1,388.07
6. Step 6: Final answer
   x = 621.28