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Finding the Fourth Proportional to 285.90, 391.97 and 280.70

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Solution

The fourth proportional to 285.90, 391.97 and 280.70 is: 384.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.90 : 391.97 = 280.70 : x
  2. Step 2: Convert to fraction form
    285.90/391.97 = 280.70/x
  3. Step 3: Cross multiply
    285.90x = 391.97 × 280.70
  4. Step 4: Simplify right side
    285.90x = 110,024.72
  5. Step 5: Solve for x
    x = 110,024.72/285.90
  6. Step 6: Final answer
    x = 384.84

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.