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Finding the Fourth Proportional to 646.88, 892.78 and 398.21

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Solution

The fourth proportional to 646.88, 892.78 and 398.21 is: 549.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.88 : 892.78 = 398.21 : x
  2. Step 2: Convert to fraction form
    646.88/892.78 = 398.21/x
  3. Step 3: Cross multiply
    646.88x = 892.78 × 398.21
  4. Step 4: Simplify right side
    646.88x = 355,513.92
  5. Step 5: Solve for x
    x = 355,513.92/646.88
  6. Step 6: Final answer
    x = 549.58

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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.