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Finding the Fourth Proportional to 420.93, 627.68 and 391.71

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Solution

The fourth proportional to 420.93, 627.68 and 391.71 is: 584.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.93 : 627.68 = 391.71 : x
  2. Step 2: Convert to fraction form
    420.93/627.68 = 391.71/x
  3. Step 3: Cross multiply
    420.93x = 627.68 × 391.71
  4. Step 4: Simplify right side
    420.93x = 245,871.87
  5. Step 5: Solve for x
    x = 245,871.87/420.93
  6. Step 6: Final answer
    x = 584.12

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.