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Finding the Fourth Proportional to 82.08, 122.40 and 78.66

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Solution

The fourth proportional to 82.08, 122.40 and 78.66 is: 117.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.08 : 122.40 = 78.66 : x
  2. Step 2: Convert to fraction form
    82.08/122.40 = 78.66/x
  3. Step 3: Cross multiply
    82.08x = 122.40 × 78.66
  4. Step 4: Simplify right side
    82.08x = 9,627.98
  5. Step 5: Solve for x
    x = 9,627.98/82.08
  6. Step 6: Final answer
    x = 117.30

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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.