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Finding the Fourth Proportional to 487.21, 671.74 and 393.61

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Solution

The fourth proportional to 487.21, 671.74 and 393.61 is: 542.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    487.21 : 671.74 = 393.61 : x
  2. Step 2: Convert to fraction form
    487.21/671.74 = 393.61/x
  3. Step 3: Cross multiply
    487.21x = 671.74 × 393.61
  4. Step 4: Simplify right side
    487.21x = 264,403.58
  5. Step 5: Solve for x
    x = 264,403.58/487.21
  6. Step 6: Final answer
    x = 542.69

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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.