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Finding the Fourth Proportional to 128.46, 192.48 and 87.66

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Solution

The fourth proportional to 128.46, 192.48 and 87.66 is: 131.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.46 : 192.48 = 87.66 : x
  2. Step 2: Convert to fraction form
    128.46/192.48 = 87.66/x
  3. Step 3: Cross multiply
    128.46x = 192.48 × 87.66
  4. Step 4: Simplify right side
    128.46x = 16,872.80
  5. Step 5: Solve for x
    x = 16,872.80/128.46
  6. Step 6: Final answer
    x = 131.35

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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.