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Finding the Fourth Proportional to 84.90, 126.66 and 81.06

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Solution

The fourth proportional to 84.90, 126.66 and 81.06 is: 120.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.90 : 126.66 = 81.06 : x
  2. Step 2: Convert to fraction form
    84.90/126.66 = 81.06/x
  3. Step 3: Cross multiply
    84.90x = 126.66 × 81.06
  4. Step 4: Simplify right side
    84.90x = 10,267.06
  5. Step 5: Solve for x
    x = 10,267.06/84.90
  6. Step 6: Final answer
    x = 120.93

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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.