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Finding the Fourth Proportional to 311.79, 429.93 and 285.33

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Solution

The fourth proportional to 311.79, 429.93 and 285.33 is: 393.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.79 : 429.93 = 285.33 : x
  2. Step 2: Convert to fraction form
    311.79/429.93 = 285.33/x
  3. Step 3: Cross multiply
    311.79x = 429.93 × 285.33
  4. Step 4: Simplify right side
    311.79x = 122,671.93
  5. Step 5: Solve for x
    x = 122,671.93/311.79
  6. Step 6: Final answer
    x = 393.44

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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.