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Finding the Fourth Proportional to 83.88, 126.42 and 78

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Solution

The fourth proportional to 83.88, 126.42 and 78 is: 117.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.88 : 126.42 = 78 : x
  2. Step 2: Convert to fraction form
    83.88/126.42 = 78/x
  3. Step 3: Cross multiply
    83.88x = 126.42 × 78
  4. Step 4: Simplify right side
    83.88x = 9,860.76
  5. Step 5: Solve for x
    x = 9,860.76/83.88
  6. Step 6: Final answer
    x = 117.56

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.