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Finding the Fourth Proportional to 72.45, 108.72 and 54.57

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Solution

The fourth proportional to 72.45, 108.72 and 54.57 is: 81.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.45 : 108.72 = 54.57 : x
  2. Step 2: Convert to fraction form
    72.45/108.72 = 54.57/x
  3. Step 3: Cross multiply
    72.45x = 108.72 × 54.57
  4. Step 4: Simplify right side
    72.45x = 5,932.85
  5. Step 5: Solve for x
    x = 5,932.85/72.45
  6. Step 6: Final answer
    x = 81.89

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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.