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Finding the Fourth Proportional to 345.12, 517.55 and 128.64

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Solution

The fourth proportional to 345.12, 517.55 and 128.64 is: 192.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.12 : 517.55 = 128.64 : x
  2. Step 2: Convert to fraction form
    345.12/517.55 = 128.64/x
  3. Step 3: Cross multiply
    345.12x = 517.55 × 128.64
  4. Step 4: Simplify right side
    345.12x = 66,576.99
  5. Step 5: Solve for x
    x = 66,576.99/345.12
  6. Step 6: Final answer
    x = 192.91

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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.