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Finding the Fourth Proportional to 128.57, 177.31 and 84.27

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Solution

The fourth proportional to 128.57, 177.31 and 84.27 is: 116.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.57 : 177.31 = 84.27 : x
  2. Step 2: Convert to fraction form
    128.57/177.31 = 84.27/x
  3. Step 3: Cross multiply
    128.57x = 177.31 × 84.27
  4. Step 4: Simplify right side
    128.57x = 14,941.91
  5. Step 5: Solve for x
    x = 14,941.91/128.57
  6. Step 6: Final answer
    x = 116.22

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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.