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Finding the Fourth Proportional to 82.02, 122.40 and 72.90

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Solution

The fourth proportional to 82.02, 122.40 and 72.90 is: 108.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.02 : 122.40 = 72.90 : x
  2. Step 2: Convert to fraction form
    82.02/122.40 = 72.90/x
  3. Step 3: Cross multiply
    82.02x = 122.40 × 72.90
  4. Step 4: Simplify right side
    82.02x = 8,922.96
  5. Step 5: Solve for x
    x = 8,922.96/82.02
  6. Step 6: Final answer
    x = 108.79

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.