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Finding the Fourth Proportional to 90.85, 136.35 and 87.87

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Solution

The fourth proportional to 90.85, 136.35 and 87.87 is: 131.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.85 : 136.35 = 87.87 : x
  2. Step 2: Convert to fraction form
    90.85/136.35 = 87.87/x
  3. Step 3: Cross multiply
    90.85x = 136.35 × 87.87
  4. Step 4: Simplify right side
    90.85x = 11,981.07
  5. Step 5: Solve for x
    x = 11,981.07/90.85
  6. Step 6: Final answer
    x = 131.88

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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.