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Finding the Fourth Proportional to 138.79, 191.53 and 91.47

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Solution

The fourth proportional to 138.79, 191.53 and 91.47 is: 126.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.79 : 191.53 = 91.47 : x
  2. Step 2: Convert to fraction form
    138.79/191.53 = 91.47/x
  3. Step 3: Cross multiply
    138.79x = 191.53 × 91.47
  4. Step 4: Simplify right side
    138.79x = 17,519.16
  5. Step 5: Solve for x
    x = 17,519.16/138.79
  6. Step 6: Final answer
    x = 126.23

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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.