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Finding the Fourth Proportional to 390.92, 538.68 and 280.08

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Solution

The fourth proportional to 390.92, 538.68 and 280.08 is: 385.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.92 : 538.68 = 280.08 : x
  2. Step 2: Convert to fraction form
    390.92/538.68 = 280.08/x
  3. Step 3: Cross multiply
    390.92x = 538.68 × 280.08
  4. Step 4: Simplify right side
    390.92x = 150,873.49
  5. Step 5: Solve for x
    x = 150,873.49/390.92
  6. Step 6: Final answer
    x = 385.94

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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.