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Finding the Fourth Proportional to 646.42, 892.20 and 397.87

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Solution

The fourth proportional to 646.42, 892.20 and 397.87 is: 549.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.42 : 892.20 = 397.87 : x
  2. Step 2: Convert to fraction form
    646.42/892.20 = 397.87/x
  3. Step 3: Cross multiply
    646.42x = 892.20 × 397.87
  4. Step 4: Simplify right side
    646.42x = 354,979.61
  5. Step 5: Solve for x
    x = 354,979.61/646.42
  6. Step 6: Final answer
    x = 549.15

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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.