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Finding the Fourth Proportional to 639.64, 882.54 and 406.78

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Solution

The fourth proportional to 639.64, 882.54 and 406.78 is: 561.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.64 : 882.54 = 406.78 : x
  2. Step 2: Convert to fraction form
    639.64/882.54 = 406.78/x
  3. Step 3: Cross multiply
    639.64x = 882.54 × 406.78
  4. Step 4: Simplify right side
    639.64x = 358,999.62
  5. Step 5: Solve for x
    x = 358,999.62/639.64
  6. Step 6: Final answer
    x = 561.25

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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.