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Finding the Fourth Proportional to 72.55, 100.12 and 39.81

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Solution

The fourth proportional to 72.55, 100.12 and 39.81 is: 54.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.55 : 100.12 = 39.81 : x
  2. Step 2: Convert to fraction form
    72.55/100.12 = 39.81/x
  3. Step 3: Cross multiply
    72.55x = 100.12 × 39.81
  4. Step 4: Simplify right side
    72.55x = 3,985.33
  5. Step 5: Solve for x
    x = 3,985.33/72.55
  6. Step 6: Final answer
    x = 54.93

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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.