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Finding the Fourth Proportional to 136.40, 204.60 and 87.80

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Solution

The fourth proportional to 136.40, 204.60 and 87.80 is: 131.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.40 : 204.60 = 87.80 : x
  2. Step 2: Convert to fraction form
    136.40/204.60 = 87.80/x
  3. Step 3: Cross multiply
    136.40x = 204.60 × 87.80
  4. Step 4: Simplify right side
    136.40x = 17,963.88
  5. Step 5: Solve for x
    x = 17,963.88/136.40
  6. Step 6: Final answer
    x = 131.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.