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Finding the Fourth Proportional to 71.72, 98.88 and 61.88

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Solution

The fourth proportional to 71.72, 98.88 and 61.88 is: 85.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.72 : 98.88 = 61.88 : x
  2. Step 2: Convert to fraction form
    71.72/98.88 = 61.88/x
  3. Step 3: Cross multiply
    71.72x = 98.88 × 61.88
  4. Step 4: Simplify right side
    71.72x = 6,118.20
  5. Step 5: Solve for x
    x = 6,118.20/71.72
  6. Step 6: Final answer
    x = 85.31

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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.