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Finding the Fourth Proportional to 87.87, 121.22 and 56.77

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Solution

The fourth proportional to 87.87, 121.22 and 56.77 is: 78.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.87 : 121.22 = 56.77 : x
  2. Step 2: Convert to fraction form
    87.87/121.22 = 56.77/x
  3. Step 3: Cross multiply
    87.87x = 121.22 × 56.77
  4. Step 4: Simplify right side
    87.87x = 6,881.07
  5. Step 5: Solve for x
    x = 6,881.07/87.87
  6. Step 6: Final answer
    x = 78.31

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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.