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Finding the Fourth Proportional to 111.87, 154.44 and 78.71

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Solution

The fourth proportional to 111.87, 154.44 and 78.71 is: 108.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.87 : 154.44 = 78.71 : x
  2. Step 2: Convert to fraction form
    111.87/154.44 = 78.71/x
  3. Step 3: Cross multiply
    111.87x = 154.44 × 78.71
  4. Step 4: Simplify right side
    111.87x = 12,155.48
  5. Step 5: Solve for x
    x = 12,155.48/111.87
  6. Step 6: Final answer
    x = 108.65

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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.