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Finding the Fourth Proportional to 71.72, 98.87 and 47.15

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Solution

The fourth proportional to 71.72, 98.87 and 47.15 is: 64.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.72 : 98.87 = 47.15 : x
  2. Step 2: Convert to fraction form
    71.72/98.87 = 47.15/x
  3. Step 3: Cross multiply
    71.72x = 98.87 × 47.15
  4. Step 4: Simplify right side
    71.72x = 4,660.99
  5. Step 5: Solve for x
    x = 4,660.99/71.72
  6. Step 6: Final answer
    x = 64.99

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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.