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Finding the Fourth Proportional to 115.61, 159.23 and 87.71

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Solution

The fourth proportional to 115.61, 159.23 and 87.71 is: 120.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.61 : 159.23 = 87.71 : x
  2. Step 2: Convert to fraction form
    115.61/159.23 = 87.71/x
  3. Step 3: Cross multiply
    115.61x = 159.23 × 87.71
  4. Step 4: Simplify right side
    115.61x = 13,965.49
  5. Step 5: Solve for x
    x = 13,965.49/115.61
  6. Step 6: Final answer
    x = 120.80

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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.