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Finding the Fourth Proportional to 128.60, 177.27 and 99.11

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Solution

The fourth proportional to 128.60, 177.27 and 99.11 is: 136.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.60 : 177.27 = 99.11 : x
  2. Step 2: Convert to fraction form
    128.60/177.27 = 99.11/x
  3. Step 3: Cross multiply
    128.60x = 177.27 × 99.11
  4. Step 4: Simplify right side
    128.60x = 17,568.34
  5. Step 5: Solve for x
    x = 17,568.34/128.60
  6. Step 6: Final answer
    x = 136.62

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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.