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Finding the Fourth Proportional to 390.78, 586.22 and 228.47

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Solution

The fourth proportional to 390.78, 586.22 and 228.47 is: 342.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 586.22 = 228.47 : x
  2. Step 2: Convert to fraction form
    390.78/586.22 = 228.47/x
  3. Step 3: Cross multiply
    390.78x = 586.22 × 228.47
  4. Step 4: Simplify right side
    390.78x = 133,929.61
  5. Step 5: Solve for x
    x = 133,929.61/390.78
  6. Step 6: Final answer
    x = 342.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.