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Finding the Fourth Proportional to 115.74, 159.71 and 78.89

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Solution

The fourth proportional to 115.74, 159.71 and 78.89 is: 108.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.74 : 159.71 = 78.89 : x
  2. Step 2: Convert to fraction form
    115.74/159.71 = 78.89/x
  3. Step 3: Cross multiply
    115.74x = 159.71 × 78.89
  4. Step 4: Simplify right side
    115.74x = 12,599.52
  5. Step 5: Solve for x
    x = 12,599.52/115.74
  6. Step 6: Final answer
    x = 108.86

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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.