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Finding the Fourth Proportional to 86.54, 128.88 and 82.08

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Solution

The fourth proportional to 86.54, 128.88 and 82.08 is: 122.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.54 : 128.88 = 82.08 : x
  2. Step 2: Convert to fraction form
    86.54/128.88 = 82.08/x
  3. Step 3: Cross multiply
    86.54x = 128.88 × 82.08
  4. Step 4: Simplify right side
    86.54x = 10,578.47
  5. Step 5: Solve for x
    x = 10,578.47/86.54
  6. Step 6: Final answer
    x = 122.24

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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.