Finding the Fourth Proportional to 1,061.78, 1,591.70 and 412.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.78 : 1,591.70 = 412.02 : x
2. Step 2: Convert to fraction form
   1,061.78/1,591.70 = 412.02/x
3. Step 3: Cross multiply
   1,061.78x = 1,591.70 × 412.02
4. Step 4: Simplify right side
   1,061.78x = 655,810.17
5. Step 5: Solve for x
   x = 655,810.17/1,061.78
6. Step 6: Final answer
   x = 617.65