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Finding the Fourth Proportional to 71.65, 98.87 and 38.90

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Solution

The fourth proportional to 71.65, 98.87 and 38.90 is: 53.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.65 : 98.87 = 38.90 : x
  2. Step 2: Convert to fraction form
    71.65/98.87 = 38.90/x
  3. Step 3: Cross multiply
    71.65x = 98.87 × 38.90
  4. Step 4: Simplify right side
    71.65x = 3,846.34
  5. Step 5: Solve for x
    x = 3,846.34/71.65
  6. Step 6: Final answer
    x = 53.68

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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.