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Finding the Fourth Proportional to 79.38, 109.48 and 54.78

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Solution

The fourth proportional to 79.38, 109.48 and 54.78 is: 75.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.38 : 109.48 = 54.78 : x
  2. Step 2: Convert to fraction form
    79.38/109.48 = 54.78/x
  3. Step 3: Cross multiply
    79.38x = 109.48 × 54.78
  4. Step 4: Simplify right side
    79.38x = 5,997.31
  5. Step 5: Solve for x
    x = 5,997.31/79.38
  6. Step 6: Final answer
    x = 75.55

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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.