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Finding the Fourth Proportional to 85.51, 127.98 and 81.05

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Solution

The fourth proportional to 85.51, 127.98 and 81.05 is: 121.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.51 : 127.98 = 81.05 : x
  2. Step 2: Convert to fraction form
    85.51/127.98 = 81.05/x
  3. Step 3: Cross multiply
    85.51x = 127.98 × 81.05
  4. Step 4: Simplify right side
    85.51x = 10,372.86
  5. Step 5: Solve for x
    x = 10,372.86/85.51
  6. Step 6: Final answer
    x = 121.31

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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.