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Finding the Fourth Proportional to 87.18, 120.37 and 65.47

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Solution

The fourth proportional to 87.18, 120.37 and 65.47 is: 90.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.18 : 120.37 = 65.47 : x
  2. Step 2: Convert to fraction form
    87.18/120.37 = 65.47/x
  3. Step 3: Cross multiply
    87.18x = 120.37 × 65.47
  4. Step 4: Simplify right side
    87.18x = 7,879.86
  5. Step 5: Solve for x
    x = 7,879.86/87.18
  6. Step 6: Final answer
    x = 90.39

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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.