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Finding the Fourth Proportional to 72.78, 109.59 and 54.87

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Solution

The fourth proportional to 72.78, 109.59 and 54.87 is: 82.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.78 : 109.59 = 54.87 : x
  2. Step 2: Convert to fraction form
    72.78/109.59 = 54.87/x
  3. Step 3: Cross multiply
    72.78x = 109.59 × 54.87
  4. Step 4: Simplify right side
    72.78x = 6,013.20
  5. Step 5: Solve for x
    x = 6,013.20/72.78
  6. Step 6: Final answer
    x = 82.62

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.