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Finding the Fourth Proportional to 261.62, 390.56 and 220.61

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Solution

The fourth proportional to 261.62, 390.56 and 220.61 is: 329.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.62 : 390.56 = 220.61 : x
  2. Step 2: Convert to fraction form
    261.62/390.56 = 220.61/x
  3. Step 3: Cross multiply
    261.62x = 390.56 × 220.61
  4. Step 4: Simplify right side
    261.62x = 86,160.04
  5. Step 5: Solve for x
    x = 86,160.04/261.62
  6. Step 6: Final answer
    x = 329.34

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.