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Finding the Fourth Proportional to 112.39, 155.34 and 87.91

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Solution

The fourth proportional to 112.39, 155.34 and 87.91 is: 121.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    112.39 : 155.34 = 87.91 : x
  2. Step 2: Convert to fraction form
    112.39/155.34 = 87.91/x
  3. Step 3: Cross multiply
    112.39x = 155.34 × 87.91
  4. Step 4: Simplify right side
    112.39x = 13,655.94
  5. Step 5: Solve for x
    x = 13,655.94/112.39
  6. Step 6: Final answer
    x = 121.50

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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.