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Finding the Fourth Proportional to 138.72, 191.45 and 83.50

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Solution

The fourth proportional to 138.72, 191.45 and 83.50 is: 115.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.72 : 191.45 = 83.50 : x
  2. Step 2: Convert to fraction form
    138.72/191.45 = 83.50/x
  3. Step 3: Cross multiply
    138.72x = 191.45 × 83.50
  4. Step 4: Simplify right side
    138.72x = 15,986.08
  5. Step 5: Solve for x
    x = 15,986.08/138.72
  6. Step 6: Final answer
    x = 115.24

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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.