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Finding the Fourth Proportional to 72.90, 100.54 and 55.42

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Solution

The fourth proportional to 72.90, 100.54 and 55.42 is: 76.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.90 : 100.54 = 55.42 : x
  2. Step 2: Convert to fraction form
    72.90/100.54 = 55.42/x
  3. Step 3: Cross multiply
    72.90x = 100.54 × 55.42
  4. Step 4: Simplify right side
    72.90x = 5,571.54
  5. Step 5: Solve for x
    x = 5,571.54/72.90
  6. Step 6: Final answer
    x = 76.43

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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.