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Finding the Fourth Proportional to 115.81, 159.86 and 78.98

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Solution

The fourth proportional to 115.81, 159.86 and 78.98 is: 109.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.81 : 159.86 = 78.98 : x
  2. Step 2: Convert to fraction form
    115.81/159.86 = 78.98/x
  3. Step 3: Cross multiply
    115.81x = 159.86 × 78.98
  4. Step 4: Simplify right side
    115.81x = 12,625.74
  5. Step 5: Solve for x
    x = 12,625.74/115.81
  6. Step 6: Final answer
    x = 109.02

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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.