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Finding the Fourth Proportional to 87.88, 121.25 and 56.81

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Solution

The fourth proportional to 87.88, 121.25 and 56.81 is: 78.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.88 : 121.25 = 56.81 : x
  2. Step 2: Convert to fraction form
    87.88/121.25 = 56.81/x
  3. Step 3: Cross multiply
    87.88x = 121.25 × 56.81
  4. Step 4: Simplify right side
    87.88x = 6,888.75
  5. Step 5: Solve for x
    x = 6,888.75/87.88
  6. Step 6: Final answer
    x = 78.39

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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.