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Finding the Fourth Proportional to 86.65, 118.70 and 85.54

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Solution

The fourth proportional to 86.65, 118.70 and 85.54 is: 117.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.65 : 118.70 = 85.54 : x
  2. Step 2: Convert to fraction form
    86.65/118.70 = 85.54/x
  3. Step 3: Cross multiply
    86.65x = 118.70 × 85.54
  4. Step 4: Simplify right side
    86.65x = 10,153.80
  5. Step 5: Solve for x
    x = 10,153.80/86.65
  6. Step 6: Final answer
    x = 117.18

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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.