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Finding the Fourth Proportional to 420.15, 630.15 and 265.61

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Solution

The fourth proportional to 420.15, 630.15 and 265.61 is: 398.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.15 : 630.15 = 265.61 : x
  2. Step 2: Convert to fraction form
    420.15/630.15 = 265.61/x
  3. Step 3: Cross multiply
    420.15x = 630.15 × 265.61
  4. Step 4: Simplify right side
    420.15x = 167,374.72
  5. Step 5: Solve for x
    x = 167,374.72/420.15
  6. Step 6: Final answer
    x = 398.37

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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.