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Finding the Fourth Proportional to 105.57, 145.67 and 77.90

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Solution

The fourth proportional to 105.57, 145.67 and 77.90 is: 107.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.57 : 145.67 = 77.90 : x
  2. Step 2: Convert to fraction form
    105.57/145.67 = 77.90/x
  3. Step 3: Cross multiply
    105.57x = 145.67 × 77.90
  4. Step 4: Simplify right side
    105.57x = 11,346.58
  5. Step 5: Solve for x
    x = 11,346.58/105.57
  6. Step 6: Final answer
    x = 107.48

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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.