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Finding the Fourth Proportional to 345.17, 517.45 and 128.61

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Solution

The fourth proportional to 345.17, 517.45 and 128.61 is: 192.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.17 : 517.45 = 128.61 : x
  2. Step 2: Convert to fraction form
    345.17/517.45 = 128.61/x
  3. Step 3: Cross multiply
    345.17x = 517.45 × 128.61
  4. Step 4: Simplify right side
    345.17x = 66,549.24
  5. Step 5: Solve for x
    x = 66,549.24/345.17
  6. Step 6: Final answer
    x = 192.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.