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Finding the Fourth Proportional to 83.18, 124.12 and 78

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Solution

The fourth proportional to 83.18, 124.12 and 78 is: 116.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.18 : 124.12 = 78 : x
  2. Step 2: Convert to fraction form
    83.18/124.12 = 78/x
  3. Step 3: Cross multiply
    83.18x = 124.12 × 78
  4. Step 4: Simplify right side
    83.18x = 9,681.36
  5. Step 5: Solve for x
    x = 9,681.36/83.18
  6. Step 6: Final answer
    x = 116.39

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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.