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Finding the Fourth Proportional to 642.96, 887.31 and 421.74

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Solution

The fourth proportional to 642.96, 887.31 and 421.74 is: 582.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.96 : 887.31 = 421.74 : x
  2. Step 2: Convert to fraction form
    642.96/887.31 = 421.74/x
  3. Step 3: Cross multiply
    642.96x = 887.31 × 421.74
  4. Step 4: Simplify right side
    642.96x = 374,214.12
  5. Step 5: Solve for x
    x = 374,214.12/642.96
  6. Step 6: Final answer
    x = 582.02

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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.