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Finding the Fourth Proportional to 127.78, 176.28 and 78.64

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Solution

The fourth proportional to 127.78, 176.28 and 78.64 is: 108.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.78 : 176.28 = 78.64 : x
  2. Step 2: Convert to fraction form
    127.78/176.28 = 78.64/x
  3. Step 3: Cross multiply
    127.78x = 176.28 × 78.64
  4. Step 4: Simplify right side
    127.78x = 13,862.66
  5. Step 5: Solve for x
    x = 13,862.66/127.78
  6. Step 6: Final answer
    x = 108.49

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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.