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Finding the Fourth Proportional to 72.78, 100.08 and 66.71

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Solution

The fourth proportional to 72.78, 100.08 and 66.71 is: 91.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.78 : 100.08 = 66.71 : x
  2. Step 2: Convert to fraction form
    72.78/100.08 = 66.71/x
  3. Step 3: Cross multiply
    72.78x = 100.08 × 66.71
  4. Step 4: Simplify right side
    72.78x = 6,675.84
  5. Step 5: Solve for x
    x = 6,675.84/72.78
  6. Step 6: Final answer
    x = 91.73

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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.