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Finding the Fourth Proportional to 390.15, 539.04 and 386.31

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Solution

The fourth proportional to 390.15, 539.04 and 386.31 is: 533.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.15 : 539.04 = 386.31 : x
  2. Step 2: Convert to fraction form
    390.15/539.04 = 386.31/x
  3. Step 3: Cross multiply
    390.15x = 539.04 × 386.31
  4. Step 4: Simplify right side
    390.15x = 208,236.54
  5. Step 5: Solve for x
    x = 208,236.54/390.15
  6. Step 6: Final answer
    x = 533.73

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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.