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Finding the Fourth Proportional to 61.85, 85.38 and 40.05

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Solution

The fourth proportional to 61.85, 85.38 and 40.05 is: 55.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.85 : 85.38 = 40.05 : x
  2. Step 2: Convert to fraction form
    61.85/85.38 = 40.05/x
  3. Step 3: Cross multiply
    61.85x = 85.38 × 40.05
  4. Step 4: Simplify right side
    61.85x = 3,419.27
  5. Step 5: Solve for x
    x = 3,419.27/61.85
  6. Step 6: Final answer
    x = 55.29

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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.