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Finding the Fourth Proportional to 84.07, 126.15 and 81.31

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Solution

The fourth proportional to 84.07, 126.15 and 81.31 is: 122.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.07 : 126.15 = 81.31 : x
  2. Step 2: Convert to fraction form
    84.07/126.15 = 81.31/x
  3. Step 3: Cross multiply
    84.07x = 126.15 × 81.31
  4. Step 4: Simplify right side
    84.07x = 10,256.85
  5. Step 5: Solve for x
    x = 10,256.85/84.07
  6. Step 6: Final answer
    x = 122.00

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.