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Finding the Fourth Proportional to 409.20, 564.45 and 261.78

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Solution

The fourth proportional to 409.20, 564.45 and 261.78 is: 361.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    409.20 : 564.45 = 261.78 : x
  2. Step 2: Convert to fraction form
    409.20/564.45 = 261.78/x
  3. Step 3: Cross multiply
    409.20x = 564.45 × 261.78
  4. Step 4: Simplify right side
    409.20x = 147,761.72
  5. Step 5: Solve for x
    x = 147,761.72/409.20
  6. Step 6: Final answer
    x = 361.10

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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.