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Finding the Fourth Proportional to 390.68, 539.22 and 280.28

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Solution

The fourth proportional to 390.68, 539.22 and 280.28 is: 386.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.68 : 539.22 = 280.28 : x
  2. Step 2: Convert to fraction form
    390.68/539.22 = 280.28/x
  3. Step 3: Cross multiply
    390.68x = 539.22 × 280.28
  4. Step 4: Simplify right side
    390.68x = 151,132.58
  5. Step 5: Solve for x
    x = 151,132.58/390.68
  6. Step 6: Final answer
    x = 386.84

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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.