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Finding the Fourth Proportional to 100.61, 138.71 and 69.47

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Solution

The fourth proportional to 100.61, 138.71 and 69.47 is: 95.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.61 : 138.71 = 69.47 : x
  2. Step 2: Convert to fraction form
    100.61/138.71 = 69.47/x
  3. Step 3: Cross multiply
    100.61x = 138.71 × 69.47
  4. Step 4: Simplify right side
    100.61x = 9,636.18
  5. Step 5: Solve for x
    x = 9,636.18/100.61
  6. Step 6: Final answer
    x = 95.78

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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.