Finding the Fourth Proportional to 1,061.78, 1,465.15 and 619.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.78 : 1,465.15 = 619.72 : x
2. Step 2: Convert to fraction form
   1,061.78/1,465.15 = 619.72/x
3. Step 3: Cross multiply
   1,061.78x = 1,465.15 × 619.72
4. Step 4: Simplify right side
   1,061.78x = 907,982.76
5. Step 5: Solve for x
   x = 907,982.76/1,061.78
6. Step 6: Final answer
   x = 855.15