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Finding the Fourth Proportional to 136.70, 188.58 and 81.40

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Solution

The fourth proportional to 136.70, 188.58 and 81.40 is: 112.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.70 : 188.58 = 81.40 : x
  2. Step 2: Convert to fraction form
    136.70/188.58 = 81.40/x
  3. Step 3: Cross multiply
    136.70x = 188.58 × 81.40
  4. Step 4: Simplify right side
    136.70x = 15,350.41
  5. Step 5: Solve for x
    x = 15,350.41/136.70
  6. Step 6: Final answer
    x = 112.29

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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.