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Finding the Fourth Proportional to 115.47, 159.21 and 78.66

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Solution

The fourth proportional to 115.47, 159.21 and 78.66 is: 108.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.47 : 159.21 = 78.66 : x
  2. Step 2: Convert to fraction form
    115.47/159.21 = 78.66/x
  3. Step 3: Cross multiply
    115.47x = 159.21 × 78.66
  4. Step 4: Simplify right side
    115.47x = 12,523.46
  5. Step 5: Solve for x
    x = 12,523.46/115.47
  6. Step 6: Final answer
    x = 108.46

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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.