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Finding the Fourth Proportional to 83, 123.70 and 78.68

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Solution

The fourth proportional to 83, 123.70 and 78.68 is: 117.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    83 : 123.70 = 78.68 : x
  2. Step 2: Convert to fraction form
    83/123.70 = 78.68/x
  3. Step 3: Cross multiply
    83x = 123.70 × 78.68
  4. Step 4: Simplify right side
    83x = 9,732.32
  5. Step 5: Solve for x
    x = 9,732.32/83
  6. Step 6: Final answer
    x = 117.26

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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.