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Finding the Fourth Proportional to 81.22, 122.54 and 77.58

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Solution

The fourth proportional to 81.22, 122.54 and 77.58 is: 117.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.22 : 122.54 = 77.58 : x
  2. Step 2: Convert to fraction form
    81.22/122.54 = 77.58/x
  3. Step 3: Cross multiply
    81.22x = 122.54 × 77.58
  4. Step 4: Simplify right side
    81.22x = 9,506.65
  5. Step 5: Solve for x
    x = 9,506.65/81.22
  6. Step 6: Final answer
    x = 117.05

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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.