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Finding the Fourth Proportional to 105.56, 145.68 and 61.90

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Solution

The fourth proportional to 105.56, 145.68 and 61.90 is: 85.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.56 : 145.68 = 61.90 : x
  2. Step 2: Convert to fraction form
    105.56/145.68 = 61.90/x
  3. Step 3: Cross multiply
    105.56x = 145.68 × 61.90
  4. Step 4: Simplify right side
    105.56x = 9,017.59
  5. Step 5: Solve for x
    x = 9,017.59/105.56
  6. Step 6: Final answer
    x = 85.43

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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.