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Finding the Fourth Proportional to 87.18, 119.53 and 85.65

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Solution

The fourth proportional to 87.18, 119.53 and 85.65 is: 117.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.18 : 119.53 = 85.65 : x
  2. Step 2: Convert to fraction form
    87.18/119.53 = 85.65/x
  3. Step 3: Cross multiply
    87.18x = 119.53 × 85.65
  4. Step 4: Simplify right side
    87.18x = 10,237.74
  5. Step 5: Solve for x
    x = 10,237.74/87.18
  6. Step 6: Final answer
    x = 117.43

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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.