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Finding the Fourth Proportional to 289.60, 400.20 and 280.12

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Solution

The fourth proportional to 289.60, 400.20 and 280.12 is: 387.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.60 : 400.20 = 280.12 : x
  2. Step 2: Convert to fraction form
    289.60/400.20 = 280.12/x
  3. Step 3: Cross multiply
    289.60x = 400.20 × 280.12
  4. Step 4: Simplify right side
    289.60x = 112,104.02
  5. Step 5: Solve for x
    x = 112,104.02/289.60
  6. Step 6: Final answer
    x = 387.10

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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.