Finding the Fourth Proportional to 1,384.31, 2,074.42 and 644.13

Step by Step Solution

1. Step 1: Write the proportion equation
   1,384.31 : 2,074.42 = 644.13 : x
2. Step 2: Convert to fraction form
   1,384.31/2,074.42 = 644.13/x
3. Step 3: Cross multiply
   1,384.31x = 2,074.42 × 644.13
4. Step 4: Simplify right side
   1,384.31x = 1,336,196.15
5. Step 5: Solve for x
   x = 1,336,196.15/1,384.31
6. Step 6: Final answer
   x = 965.24