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Finding the Fourth Proportional to 72.78, 109.20 and 55.80

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Solution

The fourth proportional to 72.78, 109.20 and 55.80 is: 83.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.78 : 109.20 = 55.80 : x
  2. Step 2: Convert to fraction form
    72.78/109.20 = 55.80/x
  3. Step 3: Cross multiply
    72.78x = 109.20 × 55.80
  4. Step 4: Simplify right side
    72.78x = 6,093.36
  5. Step 5: Solve for x
    x = 6,093.36/72.78
  6. Step 6: Final answer
    x = 83.72

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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.