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Finding the Fourth Proportional to 90.75, 136.43 and 84.07

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Solution

The fourth proportional to 90.75, 136.43 and 84.07 is: 126.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.75 : 136.43 = 84.07 : x
  2. Step 2: Convert to fraction form
    90.75/136.43 = 84.07/x
  3. Step 3: Cross multiply
    90.75x = 136.43 × 84.07
  4. Step 4: Simplify right side
    90.75x = 11,468.91
  5. Step 5: Solve for x
    x = 11,468.91/90.75
  6. Step 6: Final answer
    x = 126.38

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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.