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Finding the Fourth Proportional to 115.78, 159.73 and 81.30

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Solution

The fourth proportional to 115.78, 159.73 and 81.30 is: 112.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.78 : 159.73 = 81.30 : x
  2. Step 2: Convert to fraction form
    115.78/159.73 = 81.30/x
  3. Step 3: Cross multiply
    115.78x = 159.73 × 81.30
  4. Step 4: Simplify right side
    115.78x = 12,986.05
  5. Step 5: Solve for x
    x = 12,986.05/115.78
  6. Step 6: Final answer
    x = 112.16

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.