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Finding the Fourth Proportional to 82.80, 124.80 and 81.60

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Solution

The fourth proportional to 82.80, 124.80 and 81.60 is: 122.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.80 : 124.80 = 81.60 : x
  2. Step 2: Convert to fraction form
    82.80/124.80 = 81.60/x
  3. Step 3: Cross multiply
    82.80x = 124.80 × 81.60
  4. Step 4: Simplify right side
    82.80x = 10,183.68
  5. Step 5: Solve for x
    x = 10,183.68/82.80
  6. Step 6: Final answer
    x = 122.99

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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.