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Finding the Fourth Proportional to 128.76, 177.61 and 84.48

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Solution

The fourth proportional to 128.76, 177.61 and 84.48 is: 116.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.76 : 177.61 = 84.48 : x
  2. Step 2: Convert to fraction form
    128.76/177.61 = 84.48/x
  3. Step 3: Cross multiply
    128.76x = 177.61 × 84.48
  4. Step 4: Simplify right side
    128.76x = 15,004.49
  5. Step 5: Solve for x
    x = 15,004.49/128.76
  6. Step 6: Final answer
    x = 116.53

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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.