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Finding the Fourth Proportional to 70.91, 97.85 and 39.81

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Solution

The fourth proportional to 70.91, 97.85 and 39.81 is: 54.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.91 : 97.85 = 39.81 : x
  2. Step 2: Convert to fraction form
    70.91/97.85 = 39.81/x
  3. Step 3: Cross multiply
    70.91x = 97.85 × 39.81
  4. Step 4: Simplify right side
    70.91x = 3,895.21
  5. Step 5: Solve for x
    x = 3,895.21/70.91
  6. Step 6: Final answer
    x = 54.94

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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.