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Finding the Fourth Proportional to 83.57, 115.21 and 71.87

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Solution

The fourth proportional to 83.57, 115.21 and 71.87 is: 99.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.57 : 115.21 = 71.87 : x
  2. Step 2: Convert to fraction form
    83.57/115.21 = 71.87/x
  3. Step 3: Cross multiply
    83.57x = 115.21 × 71.87
  4. Step 4: Simplify right side
    83.57x = 8,279.39
  5. Step 5: Solve for x
    x = 8,279.39/83.57
  6. Step 6: Final answer
    x = 99.07

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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.