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Finding the Fourth Proportional to 83.90, 125.25 and 77.87

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Solution

The fourth proportional to 83.90, 125.25 and 77.87 is: 116.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.90 : 125.25 = 77.87 : x
  2. Step 2: Convert to fraction form
    83.90/125.25 = 77.87/x
  3. Step 3: Cross multiply
    83.90x = 125.25 × 77.87
  4. Step 4: Simplify right side
    83.90x = 9,753.22
  5. Step 5: Solve for x
    x = 9,753.22/83.90
  6. Step 6: Final answer
    x = 116.25

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.