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Finding the Fourth Proportional to 345.11, 517.35 and 128.64

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Solution

The fourth proportional to 345.11, 517.35 and 128.64 is: 192.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.11 : 517.35 = 128.64 : x
  2. Step 2: Convert to fraction form
    345.11/517.35 = 128.64/x
  3. Step 3: Cross multiply
    345.11x = 517.35 × 128.64
  4. Step 4: Simplify right side
    345.11x = 66,551.90
  5. Step 5: Solve for x
    x = 66,551.90/345.11
  6. Step 6: Final answer
    x = 192.85

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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.