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Finding the Fourth Proportional to 86.74, 120.52 and 85.40

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Solution

The fourth proportional to 86.74, 120.52 and 85.40 is: 118.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.74 : 120.52 = 85.40 : x
  2. Step 2: Convert to fraction form
    86.74/120.52 = 85.40/x
  3. Step 3: Cross multiply
    86.74x = 120.52 × 85.40
  4. Step 4: Simplify right side
    86.74x = 10,292.41
  5. Step 5: Solve for x
    x = 10,292.41/86.74
  6. Step 6: Final answer
    x = 118.66

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.