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Finding the Fourth Proportional to 128.62, 192.67 and 65.89

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Solution

The fourth proportional to 128.62, 192.67 and 65.89 is: 98.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.62 : 192.67 = 65.89 : x
  2. Step 2: Convert to fraction form
    128.62/192.67 = 65.89/x
  3. Step 3: Cross multiply
    128.62x = 192.67 × 65.89
  4. Step 4: Simplify right side
    128.62x = 12,695.03
  5. Step 5: Solve for x
    x = 12,695.03/128.62
  6. Step 6: Final answer
    x = 98.70

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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.