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Finding the Fourth Proportional to 99.38, 137.19 and 74.78

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Solution

The fourth proportional to 99.38, 137.19 and 74.78 is: 103.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.38 : 137.19 = 74.78 : x
  2. Step 2: Convert to fraction form
    99.38/137.19 = 74.78/x
  3. Step 3: Cross multiply
    99.38x = 137.19 × 74.78
  4. Step 4: Simplify right side
    99.38x = 10,259.07
  5. Step 5: Solve for x
    x = 10,259.07/99.38
  6. Step 6: Final answer
    x = 103.23

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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.