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Finding the Fourth Proportional to 71.40, 98.20 and 61.68

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Solution

The fourth proportional to 71.40, 98.20 and 61.68 is: 84.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.40 : 98.20 = 61.68 : x
  2. Step 2: Convert to fraction form
    71.40/98.20 = 61.68/x
  3. Step 3: Cross multiply
    71.40x = 98.20 × 61.68
  4. Step 4: Simplify right side
    71.40x = 6,056.98
  5. Step 5: Solve for x
    x = 6,056.98/71.40
  6. Step 6: Final answer
    x = 84.83

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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.