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Finding the Fourth Proportional to 128.82, 177.78 and 82.16

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Solution

The fourth proportional to 128.82, 177.78 and 82.16 is: 113.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.82 : 177.78 = 82.16 : x
  2. Step 2: Convert to fraction form
    128.82/177.78 = 82.16/x
  3. Step 3: Cross multiply
    128.82x = 177.78 × 82.16
  4. Step 4: Simplify right side
    128.82x = 14,606.40
  5. Step 5: Solve for x
    x = 14,606.40/128.82
  6. Step 6: Final answer
    x = 113.39

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.