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Finding the Fourth Proportional to 128.61, 192.92 and 113.42

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Solution

The fourth proportional to 128.61, 192.92 and 113.42 is: 170.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.61 : 192.92 = 113.42 : x
  2. Step 2: Convert to fraction form
    128.61/192.92 = 113.42/x
  3. Step 3: Cross multiply
    128.61x = 192.92 × 113.42
  4. Step 4: Simplify right side
    128.61x = 21,880.90
  5. Step 5: Solve for x
    x = 21,880.90/128.61
  6. Step 6: Final answer
    x = 170.13

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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.