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Finding the Fourth Proportional to 135.76, 203.60 and 128.40

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Solution

The fourth proportional to 135.76, 203.60 and 128.40 is: 192.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    135.76 : 203.60 = 128.40 : x
  2. Step 2: Convert to fraction form
    135.76/203.60 = 128.40/x
  3. Step 3: Cross multiply
    135.76x = 203.60 × 128.40
  4. Step 4: Simplify right side
    135.76x = 26,142.24
  5. Step 5: Solve for x
    x = 26,142.24/135.76
  6. Step 6: Final answer
    x = 192.56

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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.