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Finding the Fourth Proportional to 641.61, 885.18 and 405.49

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Solution

The fourth proportional to 641.61, 885.18 and 405.49 is: 559.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.61 : 885.18 = 405.49 : x
  2. Step 2: Convert to fraction form
    641.61/885.18 = 405.49/x
  3. Step 3: Cross multiply
    641.61x = 885.18 × 405.49
  4. Step 4: Simplify right side
    641.61x = 358,931.64
  5. Step 5: Solve for x
    x = 358,931.64/641.61
  6. Step 6: Final answer
    x = 559.42

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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.