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Finding the Fourth Proportional to 84.74, 126.50 and 78.31

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Solution

The fourth proportional to 84.74, 126.50 and 78.31 is: 116.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.74 : 126.50 = 78.31 : x
  2. Step 2: Convert to fraction form
    84.74/126.50 = 78.31/x
  3. Step 3: Cross multiply
    84.74x = 126.50 × 78.31
  4. Step 4: Simplify right side
    84.74x = 9,906.22
  5. Step 5: Solve for x
    x = 9,906.22/84.74
  6. Step 6: Final answer
    x = 116.90

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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.