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Finding the Fourth Proportional to 384.80, 529.80 and 311.36

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Solution

The fourth proportional to 384.80, 529.80 and 311.36 is: 428.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    384.80 : 529.80 = 311.36 : x
  2. Step 2: Convert to fraction form
    384.80/529.80 = 311.36/x
  3. Step 3: Cross multiply
    384.80x = 529.80 × 311.36
  4. Step 4: Simplify right side
    384.80x = 164,958.68
  5. Step 5: Solve for x
    x = 164,958.68/384.80
  6. Step 6: Final answer
    x = 428.68

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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.