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Finding the Fourth Proportional to 105.20, 145.20 and 77.66

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Solution

The fourth proportional to 105.20, 145.20 and 77.66 is: 107.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.20 : 145.20 = 77.66 : x
  2. Step 2: Convert to fraction form
    105.20/145.20 = 77.66/x
  3. Step 3: Cross multiply
    105.20x = 145.20 × 77.66
  4. Step 4: Simplify right side
    105.20x = 11,276.23
  5. Step 5: Solve for x
    x = 11,276.23/105.20
  6. Step 6: Final answer
    x = 107.19

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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.