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Finding the Fourth Proportional to 311.76, 429.60 and 307.92

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Solution

The fourth proportional to 311.76, 429.60 and 307.92 is: 424.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.76 : 429.60 = 307.92 : x
  2. Step 2: Convert to fraction form
    311.76/429.60 = 307.92/x
  3. Step 3: Cross multiply
    311.76x = 429.60 × 307.92
  4. Step 4: Simplify right side
    311.76x = 132,282.43
  5. Step 5: Solve for x
    x = 132,282.43/311.76
  6. Step 6: Final answer
    x = 424.31

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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.