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Finding the Fourth Proportional to 87.31, 120.42 and 56.23

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Solution

The fourth proportional to 87.31, 120.42 and 56.23 is: 77.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.31 : 120.42 = 56.23 : x
  2. Step 2: Convert to fraction form
    87.31/120.42 = 56.23/x
  3. Step 3: Cross multiply
    87.31x = 120.42 × 56.23
  4. Step 4: Simplify right side
    87.31x = 6,771.07
  5. Step 5: Solve for x
    x = 6,771.07/87.31
  6. Step 6: Final answer
    x = 77.55

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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.