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Finding the Fourth Proportional to 428.81, 644.42 and 417.87

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Solution

The fourth proportional to 428.81, 644.42 and 417.87 is: 627.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.81 : 644.42 = 417.87 : x
  2. Step 2: Convert to fraction form
    428.81/644.42 = 417.87/x
  3. Step 3: Cross multiply
    428.81x = 644.42 × 417.87
  4. Step 4: Simplify right side
    428.81x = 269,284.83
  5. Step 5: Solve for x
    x = 269,284.83/428.81
  6. Step 6: Final answer
    x = 627.99

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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.