Finding the Fourth Proportional to 1,005.30, 1,387.98 and 632.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.30 : 1,387.98 = 632.40 : x
2. Step 2: Convert to fraction form
   1,005.30/1,387.98 = 632.40/x
3. Step 3: Cross multiply
   1,005.30x = 1,387.98 × 632.40
4. Step 4: Simplify right side
   1,005.30x = 877,758.55
5. Step 5: Solve for x
   x = 877,758.55/1,005.30
6. Step 6: Final answer
   x = 873.13