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Finding the Fourth Proportional to 148.78, 205.29 and 128.14

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Solution

The fourth proportional to 148.78, 205.29 and 128.14 is: 176.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    148.78 : 205.29 = 128.14 : x
  2. Step 2: Convert to fraction form
    148.78/205.29 = 128.14/x
  3. Step 3: Cross multiply
    148.78x = 205.29 × 128.14
  4. Step 4: Simplify right side
    148.78x = 26,305.86
  5. Step 5: Solve for x
    x = 26,305.86/148.78
  6. Step 6: Final answer
    x = 176.81

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.