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Finding the Fourth Proportional to 646.31, 891.89 and 394.15

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Solution

The fourth proportional to 646.31, 891.89 and 394.15 is: 543.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.31 : 891.89 = 394.15 : x
  2. Step 2: Convert to fraction form
    646.31/891.89 = 394.15/x
  3. Step 3: Cross multiply
    646.31x = 891.89 × 394.15
  4. Step 4: Simplify right side
    646.31x = 351,537.20
  5. Step 5: Solve for x
    x = 351,537.20/646.31
  6. Step 6: Final answer
    x = 543.92

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.