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Finding the Fourth Proportional to 128.07, 192.05 and 87.47

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Solution

The fourth proportional to 128.07, 192.05 and 87.47 is: 131.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.07 : 192.05 = 87.47 : x
  2. Step 2: Convert to fraction form
    128.07/192.05 = 87.47/x
  3. Step 3: Cross multiply
    128.07x = 192.05 × 87.47
  4. Step 4: Simplify right side
    128.07x = 16,798.61
  5. Step 5: Solve for x
    x = 16,798.61/128.07
  6. Step 6: Final answer
    x = 131.17

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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.