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Finding the Fourth Proportional to 640.76, 884.24 and 420.08

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Solution

The fourth proportional to 640.76, 884.24 and 420.08 is: 579.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.76 : 884.24 = 420.08 : x
  2. Step 2: Convert to fraction form
    640.76/884.24 = 420.08/x
  3. Step 3: Cross multiply
    640.76x = 884.24 × 420.08
  4. Step 4: Simplify right side
    640.76x = 371,451.54
  5. Step 5: Solve for x
    x = 371,451.54/640.76
  6. Step 6: Final answer
    x = 579.70

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.