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Finding the Fourth Proportional to 109.80, 164.61 and 77.31

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Solution

The fourth proportional to 109.80, 164.61 and 77.31 is: 115.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.80 : 164.61 = 77.31 : x
  2. Step 2: Convert to fraction form
    109.80/164.61 = 77.31/x
  3. Step 3: Cross multiply
    109.80x = 164.61 × 77.31
  4. Step 4: Simplify right side
    109.80x = 12,726.00
  5. Step 5: Solve for x
    x = 12,726.00/109.80
  6. Step 6: Final answer
    x = 115.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.