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Finding the Fourth Proportional to 420.85, 631.38 and 247.66

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Solution

The fourth proportional to 420.85, 631.38 and 247.66 is: 371.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.85 : 631.38 = 247.66 : x
  2. Step 2: Convert to fraction form
    420.85/631.38 = 247.66/x
  3. Step 3: Cross multiply
    420.85x = 631.38 × 247.66
  4. Step 4: Simplify right side
    420.85x = 156,363.18
  5. Step 5: Solve for x
    x = 156,363.18/420.85
  6. Step 6: Final answer
    x = 371.55

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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.