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Finding the Fourth Proportional to 421.12, 579.85 and 321.63

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Solution

The fourth proportional to 421.12, 579.85 and 321.63 is: 442.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.12 : 579.85 = 321.63 : x
  2. Step 2: Convert to fraction form
    421.12/579.85 = 321.63/x
  3. Step 3: Cross multiply
    421.12x = 579.85 × 321.63
  4. Step 4: Simplify right side
    421.12x = 186,497.16
  5. Step 5: Solve for x
    x = 186,497.16/421.12
  6. Step 6: Final answer
    x = 442.86

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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.