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Finding the Fourth Proportional to 115.49, 159.43 and 78.15

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Solution

The fourth proportional to 115.49, 159.43 and 78.15 is: 107.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.49 : 159.43 = 78.15 : x
  2. Step 2: Convert to fraction form
    115.49/159.43 = 78.15/x
  3. Step 3: Cross multiply
    115.49x = 159.43 × 78.15
  4. Step 4: Simplify right side
    115.49x = 12,459.45
  5. Step 5: Solve for x
    x = 12,459.45/115.49
  6. Step 6: Final answer
    x = 107.88

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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.