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Finding the Fourth Proportional to 90.87, 136.17 and 84.74

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Solution

The fourth proportional to 90.87, 136.17 and 84.74 is: 126.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.87 : 136.17 = 84.74 : x
  2. Step 2: Convert to fraction form
    90.87/136.17 = 84.74/x
  3. Step 3: Cross multiply
    90.87x = 136.17 × 84.74
  4. Step 4: Simplify right side
    90.87x = 11,538.36
  5. Step 5: Solve for x
    x = 11,538.36/90.87
  6. Step 6: Final answer
    x = 126.98

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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.