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Finding the Fourth Proportional to 128.90, 177.84 and 82.28

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Solution

The fourth proportional to 128.90, 177.84 and 82.28 is: 113.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.90 : 177.84 = 82.28 : x
  2. Step 2: Convert to fraction form
    128.90/177.84 = 82.28/x
  3. Step 3: Cross multiply
    128.90x = 177.84 × 82.28
  4. Step 4: Simplify right side
    128.90x = 14,631.79
  5. Step 5: Solve for x
    x = 14,631.79/128.90
  6. Step 6: Final answer
    x = 113.52

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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.