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Finding the Fourth Proportional to 74.70, 103.17 and 72.90

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Solution

The fourth proportional to 74.70, 103.17 and 72.90 is: 100.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.70 : 103.17 = 72.90 : x
  2. Step 2: Convert to fraction form
    74.70/103.17 = 72.90/x
  3. Step 3: Cross multiply
    74.70x = 103.17 × 72.90
  4. Step 4: Simplify right side
    74.70x = 7,521.09
  5. Step 5: Solve for x
    x = 7,521.09/74.70
  6. Step 6: Final answer
    x = 100.68

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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.