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Finding the Fourth Proportional to 87.50, 120.78 and 56.41

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Solution

The fourth proportional to 87.50, 120.78 and 56.41 is: 77.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.50 : 120.78 = 56.41 : x
  2. Step 2: Convert to fraction form
    87.50/120.78 = 56.41/x
  3. Step 3: Cross multiply
    87.50x = 120.78 × 56.41
  4. Step 4: Simplify right side
    87.50x = 6,812.90
  5. Step 5: Solve for x
    x = 6,812.90/87.50
  6. Step 6: Final answer
    x = 77.86

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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.