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Finding the Fourth Proportional to 115.75, 159.78 and 77.05

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Solution

The fourth proportional to 115.75, 159.78 and 77.05 is: 106.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.75 : 159.78 = 77.05 : x
  2. Step 2: Convert to fraction form
    115.75/159.78 = 77.05/x
  3. Step 3: Cross multiply
    115.75x = 159.78 × 77.05
  4. Step 4: Simplify right side
    115.75x = 12,311.05
  5. Step 5: Solve for x
    x = 12,311.05/115.75
  6. Step 6: Final answer
    x = 106.36

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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.