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Finding the Fourth Proportional to 112.61, 155.31 and 87.66

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Solution

The fourth proportional to 112.61, 155.31 and 87.66 is: 120.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    112.61 : 155.31 = 87.66 : x
  2. Step 2: Convert to fraction form
    112.61/155.31 = 87.66/x
  3. Step 3: Cross multiply
    112.61x = 155.31 × 87.66
  4. Step 4: Simplify right side
    112.61x = 13,614.47
  5. Step 5: Solve for x
    x = 13,614.47/112.61
  6. Step 6: Final answer
    x = 120.90

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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.