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Finding the Fourth Proportional to 100.52, 138.80 and 83.91

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Solution

The fourth proportional to 100.52, 138.80 and 83.91 is: 115.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.52 : 138.80 = 83.91 : x
  2. Step 2: Convert to fraction form
    100.52/138.80 = 83.91/x
  3. Step 3: Cross multiply
    100.52x = 138.80 × 83.91
  4. Step 4: Simplify right side
    100.52x = 11,647.44
  5. Step 5: Solve for x
    x = 11,647.44/100.52
  6. Step 6: Final answer
    x = 115.87

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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.