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Finding the Fourth Proportional to 138.64, 191.20 and 103.76

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Solution

The fourth proportional to 138.64, 191.20 and 103.76 is: 143.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.64 : 191.20 = 103.76 : x
  2. Step 2: Convert to fraction form
    138.64/191.20 = 103.76/x
  3. Step 3: Cross multiply
    138.64x = 191.20 × 103.76
  4. Step 4: Simplify right side
    138.64x = 19,838.91
  5. Step 5: Solve for x
    x = 19,838.91/138.64
  6. Step 6: Final answer
    x = 143.10

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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.