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Finding the Fourth Proportional to 86.53, 130.43 and 81.31

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Solution

The fourth proportional to 86.53, 130.43 and 81.31 is: 122.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.53 : 130.43 = 81.31 : x
  2. Step 2: Convert to fraction form
    86.53/130.43 = 81.31/x
  3. Step 3: Cross multiply
    86.53x = 130.43 × 81.31
  4. Step 4: Simplify right side
    86.53x = 10,605.26
  5. Step 5: Solve for x
    x = 10,605.26/86.53
  6. Step 6: Final answer
    x = 122.56

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.