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Finding the Fourth Proportional to 289.78, 399.43 and 219.61

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Solution

The fourth proportional to 289.78, 399.43 and 219.61 is: 302.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.78 : 399.43 = 219.61 : x
  2. Step 2: Convert to fraction form
    289.78/399.43 = 219.61/x
  3. Step 3: Cross multiply
    289.78x = 399.43 × 219.61
  4. Step 4: Simplify right side
    289.78x = 87,719.60
  5. Step 5: Solve for x
    x = 87,719.60/289.78
  6. Step 6: Final answer
    x = 302.71

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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.