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Finding the Fourth Proportional to 87.48, 120.77 and 61.31

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Solution

The fourth proportional to 87.48, 120.77 and 61.31 is: 84.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.48 : 120.77 = 61.31 : x
  2. Step 2: Convert to fraction form
    87.48/120.77 = 61.31/x
  3. Step 3: Cross multiply
    87.48x = 120.77 × 61.31
  4. Step 4: Simplify right side
    87.48x = 7,403.78
  5. Step 5: Solve for x
    x = 7,403.78/87.48
  6. Step 6: Final answer
    x = 84.63

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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.