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Finding the Fourth Proportional to 420.10, 628.86 and 255.12

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Solution

The fourth proportional to 420.10, 628.86 and 255.12 is: 381.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.10 : 628.86 = 255.12 : x
  2. Step 2: Convert to fraction form
    420.10/628.86 = 255.12/x
  3. Step 3: Cross multiply
    420.10x = 628.86 × 255.12
  4. Step 4: Simplify right side
    420.10x = 160,434.76
  5. Step 5: Solve for x
    x = 160,434.76/420.10
  6. Step 6: Final answer
    x = 381.90

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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.