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Finding the Fourth Proportional to 72.28, 99.17 and 66.20

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Solution

The fourth proportional to 72.28, 99.17 and 66.20 is: 90.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.28 : 99.17 = 66.20 : x
  2. Step 2: Convert to fraction form
    72.28/99.17 = 66.20/x
  3. Step 3: Cross multiply
    72.28x = 99.17 × 66.20
  4. Step 4: Simplify right side
    72.28x = 6,565.05
  5. Step 5: Solve for x
    x = 6,565.05/72.28
  6. Step 6: Final answer
    x = 90.83

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.