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Finding the Fourth Proportional to 82.80, 114.78 and 81.30

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Solution

The fourth proportional to 82.80, 114.78 and 81.30 is: 112.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.80 : 114.78 = 81.30 : x
  2. Step 2: Convert to fraction form
    82.80/114.78 = 81.30/x
  3. Step 3: Cross multiply
    82.80x = 114.78 × 81.30
  4. Step 4: Simplify right side
    82.80x = 9,331.61
  5. Step 5: Solve for x
    x = 9,331.61/82.80
  6. Step 6: Final answer
    x = 112.70

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.