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Finding the Fourth Proportional to 390.64, 539.13 and 235.42

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Solution

The fourth proportional to 390.64, 539.13 and 235.42 is: 324.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 539.13 = 235.42 : x
  2. Step 2: Convert to fraction form
    390.64/539.13 = 235.42/x
  3. Step 3: Cross multiply
    390.64x = 539.13 × 235.42
  4. Step 4: Simplify right side
    390.64x = 126,921.98
  5. Step 5: Solve for x
    x = 126,921.98/390.64
  6. Step 6: Final answer
    x = 324.91

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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.