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Finding the Fourth Proportional to 105.21, 145.17 and 61.55

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Solution

The fourth proportional to 105.21, 145.17 and 61.55 is: 84.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.21 : 145.17 = 61.55 : x
  2. Step 2: Convert to fraction form
    105.21/145.17 = 61.55/x
  3. Step 3: Cross multiply
    105.21x = 145.17 × 61.55
  4. Step 4: Simplify right side
    105.21x = 8,934.49
  5. Step 5: Solve for x
    x = 8,934.49/105.21
  6. Step 6: Final answer
    x = 84.92

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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.