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Finding the Fourth Proportional to 390.92, 539.10 and 307.87

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Solution

The fourth proportional to 390.92, 539.10 and 307.87 is: 424.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.92 : 539.10 = 307.87 : x
  2. Step 2: Convert to fraction form
    390.92/539.10 = 307.87/x
  3. Step 3: Cross multiply
    390.92x = 539.10 × 307.87
  4. Step 4: Simplify right side
    390.92x = 165,971.37
  5. Step 5: Solve for x
    x = 165,971.37/390.92
  6. Step 6: Final answer
    x = 424.57

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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.