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Finding the Fourth Proportional to 390.62, 539.28 and 280.22

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Solution

The fourth proportional to 390.62, 539.28 and 280.22 is: 386.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.62 : 539.28 = 280.22 : x
  2. Step 2: Convert to fraction form
    390.62/539.28 = 280.22/x
  3. Step 3: Cross multiply
    390.62x = 539.28 × 280.22
  4. Step 4: Simplify right side
    390.62x = 151,117.04
  5. Step 5: Solve for x
    x = 151,117.04/390.62
  6. Step 6: Final answer
    x = 386.86

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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.