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Finding the Fourth Proportional to 90.38, 135.47 and 76.82

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Solution

The fourth proportional to 90.38, 135.47 and 76.82 is: 115.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.38 : 135.47 = 76.82 : x
  2. Step 2: Convert to fraction form
    90.38/135.47 = 76.82/x
  3. Step 3: Cross multiply
    90.38x = 135.47 × 76.82
  4. Step 4: Simplify right side
    90.38x = 10,406.32
  5. Step 5: Solve for x
    x = 10,406.32/90.38
  6. Step 6: Final answer
    x = 115.14

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.