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Finding the Fourth Proportional to 421.20, 631.09 and 189.74

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Solution

The fourth proportional to 421.20, 631.09 and 189.74 is: 284.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.20 : 631.09 = 189.74 : x
  2. Step 2: Convert to fraction form
    421.20/631.09 = 189.74/x
  3. Step 3: Cross multiply
    421.20x = 631.09 × 189.74
  4. Step 4: Simplify right side
    421.20x = 119,743.02
  5. Step 5: Solve for x
    x = 119,743.02/421.20
  6. Step 6: Final answer
    x = 284.29

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.