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Finding the Fourth Proportional to 140.20, 193.80 and 128.86

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Solution

The fourth proportional to 140.20, 193.80 and 128.86 is: 178.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.20 : 193.80 = 128.86 : x
  2. Step 2: Convert to fraction form
    140.20/193.80 = 128.86/x
  3. Step 3: Cross multiply
    140.20x = 193.80 × 128.86
  4. Step 4: Simplify right side
    140.20x = 24,973.07
  5. Step 5: Solve for x
    x = 24,973.07/140.20
  6. Step 6: Final answer
    x = 178.12

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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.