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Finding the Fourth Proportional to 86.85, 120.06 and 81.18

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Solution

The fourth proportional to 86.85, 120.06 and 81.18 is: 112.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.85 : 120.06 = 81.18 : x
  2. Step 2: Convert to fraction form
    86.85/120.06 = 81.18/x
  3. Step 3: Cross multiply
    86.85x = 120.06 × 81.18
  4. Step 4: Simplify right side
    86.85x = 9,746.47
  5. Step 5: Solve for x
    x = 9,746.47/86.85
  6. Step 6: Final answer
    x = 112.22

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.