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Finding the Fourth Proportional to 82.07, 123.15 and 78.81

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Solution

The fourth proportional to 82.07, 123.15 and 78.81 is: 118.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.07 : 123.15 = 78.81 : x
  2. Step 2: Convert to fraction form
    82.07/123.15 = 78.81/x
  3. Step 3: Cross multiply
    82.07x = 123.15 × 78.81
  4. Step 4: Simplify right side
    82.07x = 9,705.45
  5. Step 5: Solve for x
    x = 9,705.45/82.07
  6. Step 6: Final answer
    x = 118.27

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.