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Finding the Fourth Proportional to 642, 961.61 and 422.38

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Solution

The fourth proportional to 642, 961.61 and 422.38 is: 632.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    642 : 961.61 = 422.38 : x
  2. Step 2: Convert to fraction form
    642/961.61 = 422.38/x
  3. Step 3: Cross multiply
    642x = 961.61 × 422.38
  4. Step 4: Simplify right side
    642x = 406,164.83
  5. Step 5: Solve for x
    x = 406,164.83/642
  6. Step 6: Final answer
    x = 632.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.