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Finding the Fourth Proportional to 431.76, 647.68 and 239.28

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Solution

The fourth proportional to 431.76, 647.68 and 239.28 is: 358.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.76 : 647.68 = 239.28 : x
  2. Step 2: Convert to fraction form
    431.76/647.68 = 239.28/x
  3. Step 3: Cross multiply
    431.76x = 647.68 × 239.28
  4. Step 4: Simplify right side
    431.76x = 154,976.87
  5. Step 5: Solve for x
    x = 154,976.87/431.76
  6. Step 6: Final answer
    x = 358.94

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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.