Finding the Fourth Proportional to 1,385.69, 1,912.23 and 756.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.69 : 1,912.23 = 756.21 : x
2. Step 2: Convert to fraction form
   1,385.69/1,912.23 = 756.21/x
3. Step 3: Cross multiply
   1,385.69x = 1,912.23 × 756.21
4. Step 4: Simplify right side
   1,385.69x = 1,446,047.45
5. Step 5: Solve for x
   x = 1,446,047.45/1,385.69
6. Step 6: Final answer
   x = 1,043.56