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Finding the Fourth Proportional to 421.61, 629.71 and 397.91

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Solution

The fourth proportional to 421.61, 629.71 and 397.91 is: 594.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.61 : 629.71 = 397.91 : x
  2. Step 2: Convert to fraction form
    421.61/629.71 = 397.91/x
  3. Step 3: Cross multiply
    421.61x = 629.71 × 397.91
  4. Step 4: Simplify right side
    421.61x = 250,568.49
  5. Step 5: Solve for x
    x = 250,568.49/421.61
  6. Step 6: Final answer
    x = 594.32

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.