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Finding the Fourth Proportional to 115.16, 158.96 and 78.31

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Solution

The fourth proportional to 115.16, 158.96 and 78.31 is: 108.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.16 : 158.96 = 78.31 : x
  2. Step 2: Convert to fraction form
    115.16/158.96 = 78.31/x
  3. Step 3: Cross multiply
    115.16x = 158.96 × 78.31
  4. Step 4: Simplify right side
    115.16x = 12,447.94
  5. Step 5: Solve for x
    x = 12,447.94/115.16
  6. Step 6: Final answer
    x = 108.09

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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.