Finding the Fourth Proportional to 1,064.78, 1,469.42 and 645.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,064.78 : 1,469.42 = 645.05 : x
2. Step 2: Convert to fraction form
   1,064.78/1,469.42 = 645.05/x
3. Step 3: Cross multiply
   1,064.78x = 1,469.42 × 645.05
4. Step 4: Simplify right side
   1,064.78x = 947,838.80
5. Step 5: Solve for x
   x = 947,838.80/1,064.78
6. Step 6: Final answer
   x = 890.18