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Finding the Fourth Proportional to 83.78, 115.65 and 54.68

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Solution

The fourth proportional to 83.78, 115.65 and 54.68 is: 75.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.78 : 115.65 = 54.68 : x
  2. Step 2: Convert to fraction form
    83.78/115.65 = 54.68/x
  3. Step 3: Cross multiply
    83.78x = 115.65 × 54.68
  4. Step 4: Simplify right side
    83.78x = 6,323.74
  5. Step 5: Solve for x
    x = 6,323.74/83.78
  6. Step 6: Final answer
    x = 75.48

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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.