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Finding the Fourth Proportional to 86.90, 119.13 and 85.55

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Solution

The fourth proportional to 86.90, 119.13 and 85.55 is: 117.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.90 : 119.13 = 85.55 : x
  2. Step 2: Convert to fraction form
    86.90/119.13 = 85.55/x
  3. Step 3: Cross multiply
    86.90x = 119.13 × 85.55
  4. Step 4: Simplify right side
    86.90x = 10,191.14
  5. Step 5: Solve for x
    x = 10,191.14/86.90
  6. Step 6: Final answer
    x = 117.27

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.