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Finding the Fourth Proportional to 78.20, 108.17 and 63.98

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Solution

The fourth proportional to 78.20, 108.17 and 63.98 is: 88.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.20 : 108.17 = 63.98 : x
  2. Step 2: Convert to fraction form
    78.20/108.17 = 63.98/x
  3. Step 3: Cross multiply
    78.20x = 108.17 × 63.98
  4. Step 4: Simplify right side
    78.20x = 6,920.40
  5. Step 5: Solve for x
    x = 6,920.40/78.20
  6. Step 6: Final answer
    x = 88.50

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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.