Finding the Fourth Proportional to 1,065.78, 1,470.80 and 646.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,065.78 : 1,470.80 = 646.05 : x
2. Step 2: Convert to fraction form
   1,065.78/1,470.80 = 646.05/x
3. Step 3: Cross multiply
   1,065.78x = 1,470.80 × 646.05
4. Step 4: Simplify right side
   1,065.78x = 950,210.34
5. Step 5: Solve for x
   x = 950,210.34/1,065.78
6. Step 6: Final answer
   x = 891.56