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Finding the Fourth Proportional to 72.88, 109.20 and 55.78

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Solution

The fourth proportional to 72.88, 109.20 and 55.78 is: 83.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.88 : 109.20 = 55.78 : x
  2. Step 2: Convert to fraction form
    72.88/109.20 = 55.78/x
  3. Step 3: Cross multiply
    72.88x = 109.20 × 55.78
  4. Step 4: Simplify right side
    72.88x = 6,091.18
  5. Step 5: Solve for x
    x = 6,091.18/72.88
  6. Step 6: Final answer
    x = 83.58

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.