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Finding the Fourth Proportional to 642.60, 887.22 and 421.92

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Solution

The fourth proportional to 642.60, 887.22 and 421.92 is: 582.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.60 : 887.22 = 421.92 : x
  2. Step 2: Convert to fraction form
    642.60/887.22 = 421.92/x
  3. Step 3: Cross multiply
    642.60x = 887.22 × 421.92
  4. Step 4: Simplify right side
    642.60x = 374,335.86
  5. Step 5: Solve for x
    x = 374,335.86/642.60
  6. Step 6: Final answer
    x = 582.53

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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.