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Finding the Fourth Proportional to 128.70, 177.57 and 99.54

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Solution

The fourth proportional to 128.70, 177.57 and 99.54 is: 137.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.70 : 177.57 = 99.54 : x
  2. Step 2: Convert to fraction form
    128.70/177.57 = 99.54/x
  3. Step 3: Cross multiply
    128.70x = 177.57 × 99.54
  4. Step 4: Simplify right side
    128.70x = 17,675.32
  5. Step 5: Solve for x
    x = 17,675.32/128.70
  6. Step 6: Final answer
    x = 137.34

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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.