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Finding the Fourth Proportional to 390.70, 539.10 and 243.38

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Solution

The fourth proportional to 390.70, 539.10 and 243.38 is: 335.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.70 : 539.10 = 243.38 : x
  2. Step 2: Convert to fraction form
    390.70/539.10 = 243.38/x
  3. Step 3: Cross multiply
    390.70x = 539.10 × 243.38
  4. Step 4: Simplify right side
    390.70x = 131,206.16
  5. Step 5: Solve for x
    x = 131,206.16/390.70
  6. Step 6: Final answer
    x = 335.82

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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.