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Finding the Fourth Proportional to 311.85, 469.80 and 285.12

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Solution

The fourth proportional to 311.85, 469.80 and 285.12 is: 429.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.85 : 469.80 = 285.12 : x
  2. Step 2: Convert to fraction form
    311.85/469.80 = 285.12/x
  3. Step 3: Cross multiply
    311.85x = 469.80 × 285.12
  4. Step 4: Simplify right side
    311.85x = 133,949.38
  5. Step 5: Solve for x
    x = 133,949.38/311.85
  6. Step 6: Final answer
    x = 429.53

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.