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Finding the Fourth Proportional to 390.64, 539.07 and 213.59

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Solution

The fourth proportional to 390.64, 539.07 and 213.59 is: 294.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 539.07 = 213.59 : x
  2. Step 2: Convert to fraction form
    390.64/539.07 = 213.59/x
  3. Step 3: Cross multiply
    390.64x = 539.07 × 213.59
  4. Step 4: Simplify right side
    390.64x = 115,138.89
  5. Step 5: Solve for x
    x = 115,138.89/390.64
  6. Step 6: Final answer
    x = 294.75

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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.