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Finding the Fourth Proportional to 390.54, 538.20 and 279.82

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Solution

The fourth proportional to 390.54, 538.20 and 279.82 is: 385.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.54 : 538.20 = 279.82 : x
  2. Step 2: Convert to fraction form
    390.54/538.20 = 279.82/x
  3. Step 3: Cross multiply
    390.54x = 538.20 × 279.82
  4. Step 4: Simplify right side
    390.54x = 150,596.97
  5. Step 5: Solve for x
    x = 150,596.97/390.54
  6. Step 6: Final answer
    x = 385.62

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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.