Finding the Fourth Proportional to 1,000.72, 1,379.72 and 646.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,000.72 : 1,379.72 = 646.04 : x
2. Step 2: Convert to fraction form
   1,000.72/1,379.72 = 646.04/x
3. Step 3: Cross multiply
   1,000.72x = 1,379.72 × 646.04
4. Step 4: Simplify right side
   1,000.72x = 891,354.31
5. Step 5: Solve for x
   x = 891,354.31/1,000.72
6. Step 6: Final answer
   x = 890.71