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Finding the Fourth Proportional to 82.20, 123.80 and 72.66

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Solution

The fourth proportional to 82.20, 123.80 and 72.66 is: 109.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.20 : 123.80 = 72.66 : x
  2. Step 2: Convert to fraction form
    82.20/123.80 = 72.66/x
  3. Step 3: Cross multiply
    82.20x = 123.80 × 72.66
  4. Step 4: Simplify right side
    82.20x = 8,995.41
  5. Step 5: Solve for x
    x = 8,995.41/82.20
  6. Step 6: Final answer
    x = 109.44

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.