Finding the Fourth Proportional to 1,043.69, 1,439.67 and 645.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,043.69 : 1,439.67 = 645.50 : x
2. Step 2: Convert to fraction form
   1,043.69/1,439.67 = 645.50/x
3. Step 3: Cross multiply
   1,043.69x = 1,439.67 × 645.50
4. Step 4: Simplify right side
   1,043.69x = 929,313.00
5. Step 5: Solve for x
   x = 929,313.00/1,043.69
6. Step 6: Final answer
   x = 890.42