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Finding the Fourth Proportional to 80.39, 111.06 and 71.68

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Solution

The fourth proportional to 80.39, 111.06 and 71.68 is: 99.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.39 : 111.06 = 71.68 : x
  2. Step 2: Convert to fraction form
    80.39/111.06 = 71.68/x
  3. Step 3: Cross multiply
    80.39x = 111.06 × 71.68
  4. Step 4: Simplify right side
    80.39x = 7,960.78
  5. Step 5: Solve for x
    x = 7,960.78/80.39
  6. Step 6: Final answer
    x = 99.03

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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.