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Finding the Fourth Proportional to 641.69, 885.94 and 405.74

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Solution

The fourth proportional to 641.69, 885.94 and 405.74 is: 560.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.69 : 885.94 = 405.74 : x
  2. Step 2: Convert to fraction form
    641.69/885.94 = 405.74/x
  3. Step 3: Cross multiply
    641.69x = 885.94 × 405.74
  4. Step 4: Simplify right side
    641.69x = 359,462.50
  5. Step 5: Solve for x
    x = 359,462.50/641.69
  6. Step 6: Final answer
    x = 560.18

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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.