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Finding the Fourth Proportional to 61.70, 85.15 and 42.05

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Solution

The fourth proportional to 61.70, 85.15 and 42.05 is: 58.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.70 : 85.15 = 42.05 : x
  2. Step 2: Convert to fraction form
    61.70/85.15 = 42.05/x
  3. Step 3: Cross multiply
    61.70x = 85.15 × 42.05
  4. Step 4: Simplify right side
    61.70x = 3,580.67
  5. Step 5: Solve for x
    x = 3,580.67/61.70
  6. Step 6: Final answer
    x = 58.04

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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.