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Finding the Fourth Proportional to 642.07, 885.17 and 405.90

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Solution

The fourth proportional to 642.07, 885.17 and 405.90 is: 559.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.07 : 885.17 = 405.90 : x
  2. Step 2: Convert to fraction form
    642.07/885.17 = 405.90/x
  3. Step 3: Cross multiply
    642.07x = 885.17 × 405.90
  4. Step 4: Simplify right side
    642.07x = 359,292.67
  5. Step 5: Solve for x
    x = 359,292.67/642.07
  6. Step 6: Final answer
    x = 559.58

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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.