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Finding the Fourth Proportional to 420.34, 630.31 and 127.79

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Solution

The fourth proportional to 420.34, 630.31 and 127.79 is: 191.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.34 : 630.31 = 127.79 : x
  2. Step 2: Convert to fraction form
    420.34/630.31 = 127.79/x
  3. Step 3: Cross multiply
    420.34x = 630.31 × 127.79
  4. Step 4: Simplify right side
    420.34x = 80,546.68
  5. Step 5: Solve for x
    x = 80,546.68/420.34
  6. Step 6: Final answer
    x = 191.62

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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.