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Finding the Fourth Proportional to 115.78, 159.79 and 66.65

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Solution

The fourth proportional to 115.78, 159.79 and 66.65 is: 91.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.78 : 159.79 = 66.65 : x
  2. Step 2: Convert to fraction form
    115.78/159.79 = 66.65/x
  3. Step 3: Cross multiply
    115.78x = 159.79 × 66.65
  4. Step 4: Simplify right side
    115.78x = 10,650.07
  5. Step 5: Solve for x
    x = 10,650.07/115.78
  6. Step 6: Final answer
    x = 91.99

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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.