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Finding the Fourth Proportional to 100.29, 138.45 and 67.15

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Solution

The fourth proportional to 100.29, 138.45 and 67.15 is: 92.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.29 : 138.45 = 67.15 : x
  2. Step 2: Convert to fraction form
    100.29/138.45 = 67.15/x
  3. Step 3: Cross multiply
    100.29x = 138.45 × 67.15
  4. Step 4: Simplify right side
    100.29x = 9,296.58
  5. Step 5: Solve for x
    x = 9,296.58/100.29
  6. Step 6: Final answer
    x = 92.70

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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.